Harry Potter is at the Dursleys' for the summer, spending his time studying new spells undercover. When Uncle Vernon's sister, Marge, comes for a visit and infuriates Harry by insulting his parents, he accidentally causes her to inflate and fly away. Harry loses his temper and threatens to curse Vernon but flees, fed up with his life at Privet Drive. The Knight Bus appears and delivers Harry to the Leaky Cauldron, where Minister of Magic Cornelius Fudge tells him he will not be arrested. During the summer, his friends Ron Weasley and Hermione Granger go to the Leaky Cauldron too. Harry also learns that Sirius Black, a convicted supporter of Lord Voldemort, has escaped Azkaban prison and is likely intending to kill Harry.
Harry, Ron, and Hermione head back to school on the Hogwarts Express. They unknowingly share a compartment with the new Defense Against the Dark Arts teacher, Remus Lupin. When the train abruptly stops, Dementors (the guards of Azkaban) board, searching for Black. Harry faints when one Dementor enters their compartment, but Lupin repels it with a charm.
At Hogwarts, Albus Dumbledore informs students that the Dementors will be guarding the school while Black is at large. Professor Lupin is introduced, and Hagrid is announced as the new Care of Magical Creatures teacher. Lupin's lessons prove enjoyable; he focuses on practice, not just theory, and encourages less confident students such as Neville. However, Hagrid's first class goes awry when Draco Malfoy deliberately provokes the Hippogriff, Buckbeak, who then attacks him. Draco's father Lucius Malfoy has Buckbeak sentenced to death.
During a Quidditch match, several Dementors approach Harry, causing him to fall off his broomstick, which is destroyed by the Whomping Willow. Lupin teaches Harry to defend himself against Dementors with a Patronus charm. Because Harry lacks parental permission to visit Hogsmeade, Fred and George (who intercept him despite his invisible cloak due to his footprints in the snow) give him their Marauder's Map, a magical document showing every person's location within Hogwarts, as well as secret passageways in and out of the castle. At Hogsmeade, Harry overhears that Black is his godfather and was his parents' best friend. Black was accused of divulging the Potters' secret whereabouts to Voldemort and murdering their mutual friend Peter Pettigrew. Harry vows to kill Black.
As Harry is leaving his Divination final exam, Professor Trelawney enters a trance and predicts that the Dark Lord's servant will return that night. Later, Harry, Ron, and Hermione visit Hagrid to console him over Buckbeak's impending execution. While there, they discover Scabbers, Ron's missing rat. Fudge, Dumbledore, and an executioner arrive at Hagrid's to carry out Buckbeak's execution, and the three students hurry away to avoid being discovered. Scabbers suddenly bites Ron and escapes, the trio chase him. A large dog appears and drags both Ron and Scabbers into a hole at the Whomping Willow's base. Harry and Hermione follow them through an underground passage to the Shrieking Shack.
There they discover that the dog is actually Sirius Black, who is an Animagus. Harry attacks Black, but Lupin arrives and disarms Harry. After exchanging a few cryptic words with Black, Lupin then embraces him as an old friend. When confronted by Hermione, Lupin admits to being a werewolf, and he and Black begin to explain that Black is innocent. Professor Snape bursts in, intending to hand over Black to the Dementors, but Harry, having begun to believe Lupin and Black, knocks him out with a spell. Lupin and Black explain that Scabbers is actually Peter Pettigrew, an Animagus who committed the crime for which Black was convicted.
Lupin and Black force Pettigrew back into his human form preparatory to killing him, but Harry intervenes saying that his father, James Potter, would not have wanted his two best friends to become killers. Pettigrew was then to be turned over to the Dementors. As the group heads to the castle, the full moon rises; Lupin transforms into a werewolf, and Pettigrew manages to escape. Lupin and Black fight in their animal forms, until Lupin is distracted by another animal's howls. Dementors attack Black and Harry. As Dementors are preparing to suck out their souls & perform the Dementor's Kiss, Harry sees a distant figure cast a powerful stag-shaped Patronus that scatters the Dementors. Harry believes the mysterious figure is his dead father.
Harry passes out from the trauma, and awakens to find he is in Hogwarts and Sirius was captured. Acting on advice from Dumbledore, Hermione reveals that she possesses a time-turner that she has used all year to take multiple classes simultaneously. She and Harry travel back in time three hours, watching themselves repeat that night's events. They free Buckbeak, and return to the Whomping Willow. As the Dementors descend to attack Black and his "other" self & prepare the Dementor's Kiss from the previous events, Harry realises that he himself was the one to cast the Patronus, and rushes to do so to prevent his other self from experiencing the Dementor's Kiss & remove his own existence. Harry and Hermione rescue Black, who escapes on Buckbeak. Lupin resigns the next day, knowing that parents will object to a werewolf teaching their children. Shortly after, Black sends Harry a Firebolt, the fastest racing broom ever made.
With Prisoner of Azkaban production of the Harry Potter films switched to an 18-month cycle, which producer David Heyman explained was "to give each film the time it required." Chris Columbus, the director of the previous two films, decided not to return and helm the third instalment as he "hadn't seen his own kids for supper in the week for about two and a half years." Even so, he remained on as a producer alongside Heyman. Guillermo del Toro was approached to direct, but considered the film "so bright and happy and full of light, that he wasn't interested." Marc Forster turned down the film because he had made Finding Neverland and did not want to direct child actors again. Before filming began, Cuaron asked each of the three leads to write an essay about their character in first person, to better understand them. Emma Watson turned in a 16-page essay, Daniel Radcliffe turned in a simple one page summary, and Rupert Grint never wrote one. Warner Bros. then composed a three-name short list for Columbus's replacement, which comprised Callie Khouri, Kenneth Branagh (who played Gilderoy Lockhart in Chamber of Secrets) and eventual selection Alfonso Cuarón. Cuarón was initially nervous about accepting as he had not read any of the books, or seen the films. After reading the series, he changed his mind and signed on to direct, as he had immediately connected to the story. Cuarón's appointment pleased J. K. Rowling who loved his film Y tu mamá también and was impressed with his adaptation of A Little Princess. Heyman found that "tonally and stylistically, Cuarón was the perfect fit."
Principal photography began on 24 February 2003, at Leavesden Film Studios, and concluded in October 2003.
Some sets for the film were built in Glen Coe, Scotland, near the Clachaig Inn. The indoor sets, including ones built for the previous two films, are mainly in Leavesden Film Studios. The Hogwarts Lake was filmed from Loch Shiel, Loch Eilt and Loch Morar in the Highlands of Scotland. Incidentally, the train bridge, which was also featured in the Chamber of Secrets movie, is opposite Loch Shiel and was used to film the sequences when the Dementor boarded the train. A small section of the triple-decker bus scene, where it weaves in between traffic, was filmed in Palmers Green in North London. Some parts were also filmed in and around Borough Market and Lambeth Bridge in London.
The Honeydukes set in this film is a redress of the set of Flourish & Blotts that was seen in Harry Potter and the Chamber of Secrets, which, in turn, was a redress of the Ollivanders set from the first film.
Rowling allowed Cuarón to make minor changes to the book, on the condition that he stuck to the book's spirit. She allowed him to place a sundial on the Hogwarts' grounds, but rejected a graveyard, as that would play an important part in the then unreleased sixth book. Rowling said she "got goosebumps" when she saw several moments in the film, as they inadvertently referred to events in the final two books, she stated "people are going to look back on the film and think that those were put in deliberately as clues." When filming concluded, Cuarón found that it had "been the two sweetest years of my life," and expressed his interest in directing one of the sequels.
Cuarón originally wanted to move away from CGI toward puppetry. He hired master underwater puppeteer Basil Twist to help, using puppets to study the potential movement of the Dementors. Once it became apparent that puppetry would be too expensive and unable to portray the specific elements of the Dementors, Cuarón turned to CGI; however, he and his team did use footage of Dementor puppets underwater as a basis for the flowing movements of the computer-generated Dementors.
The Knight Bus segment when Harry is being taken to The Leaky Cauldron uses the film technique known as bullet time, popularised in The Matrix series of films. This segment takes humorous advantage of the magic quality of the Harry Potter world by having the Muggle world go into bullet time while inside the Knight Bus, Harry, Stan Shunpike and Ernie Prang (and the talking shrunken head) keep moving in real time.
The Academy Award nominated score was the third and final Potter score to be composed and conducted by John Williams and released on CD on 25 May 2004. In general, his music for this third film is not as bright as that of the previous films, with distinct medieval influences in the instrumentation. One of the new themes, "Double Trouble," was written during production so that a children's choir could perform it in Hogwarts's Great Hall in one of the film's earlier scenes. There are brief quotes of themes from the earlier films, but the majority of the material in this score is new, including statements of "Double Trouble" and several other entirely new themes.
Brand X Music scored the trailers, using the tracks "Anticipation" and "Progeny".
Prisoner of Azkaban was, at the time of publication, the longest book in the series. The increasing plot complexity necessitated a looser adaptation of the book's finer plot lines and back-story. The film opens with Harry using magic to light his wand in short bursts, in the same scene in the book he uses a torch as performing magic is illegal for wizards under the age of seventeen. Also In the book, there is no shrunken head in the night bus, while in the movie, a rude shrunken head talks through most of the Knight bus scene. The connection between Harry's parents and the Marauder's map is only briefly mentioned, as is Remus Lupin's association to both the map and James Potter. Additionally, it was never mentioned as to who the Marauders were or who the nicknames (Mooney, Wormtail, Padfoot, and Prongs) belonged to. Some exposition was removed for dramatic effect: both the Shrieking Shack and Scabbers the rat are mentioned only very briefly in the film adaptation, while they receive a more thorough coverage in the novel. Most of the back story of Sirius Black is also cut, with no mention of the manner of his escape from Azkaban.
On account of pace and time considerations, the film glosses over detailed descriptions of magical education. Only one Hippogriff, Buckbeak, is seen, and only Malfoy and Harry are seen interacting with the Hippogriff during Care of Magical Creatures lessons, and most other lessons, including all of Snape's potions classes, were cut from the film. The complicated description of the Fidelius Charm is removed entirely from the film adaptation, with no explanation given of exactly how Black betrayed the Potters to Lord Voldemort. Many of the lines in this scene are redistributed amongst Cornelius Fudge and Minerva McGonagall; in compensation, McGonagall's exposition of the Animagus transformation is instead given by Snape.
The embryonic romantic connection between Ron and Hermione is more prominent in the film adaptation than the original book; in response to criticism of the first two films for sacrificing character development for mystery and adventure, the emotional development of all three lead characters is given more attention in the third film. However, some critics and fans thought that the result was a murky plotline. That said, any mention of the beginnings of Harry's crush on Cho Chang is removed. Cedric Diggory also did not appear in the films until the following film, and thus, his father Amos is a much nicer person in the next film than in the next book, as Cedric did not beat Harry. The darker side of Harry is first glimpsed in this film, when Harry proclaims, "I hope he Black finds me. Cause when he does, I'm gonna be ready. When he does, I'm gonna kill him!". Also, Harry receives the Firebolt at the end of the film, while in the book he receives it anonymously at Christmas and it is confiscated for a few weeks to be checked for possible jinxes by Professor Flitwick and Madam Hooch.
Emma Thompson accepted the role of Professor Trelawney to impress her four-year-old daughter, Gaia Wise. Tilda Swinton was originally offered the role but declined.
Other directors reportedly considered for this installment of the Harry Potter series included Callie Khouri and Kenneth Branagh, star of Harry Potter and the Chamber of Secrets.
Dudley Dursley has no lines. He only laughs at the TV and gives two gasps of surprise.
The effects team spent six months creating the dementors. Originally, Alfonso Cuarón wasn't thrilled with the idea of using CGI and wanted to use more traditional techniques such as puppetry. The filmmakers tried a basic technique with a dementor puppet floating in the breeze but weren't satisfied with the way it looked. Puppeteer Basil Twist showed them a technique that involved putting the puppet in water and shooting it in slow motion with the film reversed. The filmmakers liked the way it looked but realized that this would be an impossible task, so in the end they decided to use CGI to create the dementors.
Honeydukes "is floor-to-ceiling psychedelia" and includes Mexican skulls made of sugar. The cast was told that the Honeydukes candy was lacquer-coated, when in fact it wasn't, to prevent candy from disappearing between takes.
Illusionist Paul Kieve served as a consultant. He taught magic to several members of the cast including Daniel Radcliffe and Emma Watson (Harry and Hermione) and worked extensively to create physical magical effects. He is the first illusionist to have worked on any of the series of films. He is also to make a cameo appearance in the film in a scene in the Three Broomsticks pub.
Filming was halted following the vandalization of the train used as the Hogwarts Express.
The set for Honeydukes was previously used as Olivander's Wand Shop in Harry Potter and the Sorcerer's Stone, and Flourish and Blotts in Harry Potter and the Chamber of Secrets.
David Thewlis was originally considered to play Professor Quirrell in Harry Potter and the Sorcerer's Stone.
The film was offered to director Guillermo del Toro but he opted to do Hellboy instead.
Marc Forster was offered the job of directing this film but declined and did Finding Neverland instead.
The tattoos on Sirius Black's body and hands are borrowed from Russian prison gangs. They are markings which identify the person as a man to be feared and respected.
Gary Oldman says he accepted the role of Sirius Black because he "needed the work". He hadn't acted for over a year. His last film was Sin, which was filmed in 2002.
Alfonso Cuarón coached Daniel Radcliffe in one scene where the latter had to act awed: "Pretend you're seeing Cameron Diaz in a G-string". It worked.
Executive producer Chris Columbus (who directed the first two films) offered the role of director to Alfonso Cuarón after watching Cuarón's A Little Princess.
Alfonso Cuarón had never read the Harry Potter books or seen the first two movies when he was offered the job of director.
When we see the Marauder's Map for the first time, the name 'Newt Scamander' can be seen. In the Harry Potter universe, he wrote the book "Fantastic Beasts and Where To Find Them", but isn't a teacher at Hogwarts.
Because he would be overseeing this film's post-production work, director Alfonso Cuarón declined the offer to direct Harry Potter and the Goblet of Fire. Mike Newell was then chosen by Warner Brothers.
The German subsidary of Warner Bros. tried to cut down the film (as they did with Harry Potter and the Chamber of Secrets) to secure a more commercial "Not under 6" rating. They submitted several versions but all were rejected by the German ratings board FSK for this rating. In the end the uncut version was released with a "Not under 12" rating.
Broke UK box office records when it grossed £5.3 million in its opening day of release on 31 May 2004, making it the biggest opening day and single day of all time.
Warner Brothers supplied ushers at cinemas with night vision goggles to prevent illegal recording and pirating of the film.
The rating in the Netherlands for this film is "not under 9". This rating was created especially for the film, since it was judged to be too scary for 6 year olds and the next rating, "not under 12", would exclude too much of the target audience.
Aware of his fondness for music, Gary Oldman presented Daniel Radcliffe with a bass guitar as a gift when they met.
In the scene where Harry is given the Marauder's Map by the Weasley twins, the name "Moony" is misspelled as "Mooney". While not really a mistake, there is still an interesting connection. The film's visual effects supervisor is named Karl Mooney. The spelling was changed deliberately for the in-joke.
The set for the sequence where Professor Lupin teaches Harry to defend against the dementors previously served as Dumbledore's office in Harry Potter and the Chamber of Secrets.
Sir Cadogan, played by Paul Whitehouse, was cut almost completely out of the film. You do still see Sir Cadogan jump into the shot of Ron, Harry and Hermione right after Ginny tells them the Fat Lady is gone. He appears in a picture behind them.
A fire near the Glenfinnan viaduct in Scotland delayed filming of the Hogwarts Express scenes for a day.
Two Knight Buses were built: one for exterior shots and one for interior shots. The exterior of the bus was created by taking an ordinary double-decker London bus, adding a level, and painting it purple.
Ian McKellen turned down the role of Dumbledore. Having appeared as Gandalf in The Lord of the Rings, he said, "I had enough trouble living up to one legend. Two would be too much to hope for."
Ron's dream about spiders making him tap-dance is a two-in-one reference of the next book. In 'Goblet of Fire' there is an unforgivable curse where you can control what someone does, taught by Professor Moody. He makes a spider tap-dance on the desk
Prior to its release, material related to the film was labeled with the code title "Radiator Blues".
Professor Dumbledore seemingly stalls the executioner by saying that he needs to sign the execution order, and that he has "a very long name". In Harry Potter and the Order of the Phoenix, his full name is revealed to be Albus Percival Wulfric Brian Dumbledore.
During the scene where we first meet Buckbeak the Hippogriff, just after Ron pushes Harry forward there is a shot of the animal pooping. The CGI team believes this might be the first example of a CGI animal doing this, but the BBC miniseries Walking with Dinosaurs had done it first.
Alfonso Cuarón had an idea for there to be tiny people inhabiting Hogwarts, and jumping on piano keys in one scene. J.K. Rowling firmly vetoed it, saying tiny people were completely foreign to the world of her books.
When Chris Columbus was still slated to direct, Robson Green was considered for the role of Sirius Black.
Shot entirely on wide-angle lenses. The length of the lenses ranged between 14-24mm and never beyond that. Alfonso Cuarón insisted on the wide-angles because he wanted to let the audience see the foreground and the background.
During the filming of the sleeping bag scene, director Alfonso Cuarón and Alan Rickman played a practical joke on Daniel Radcliffe by hiding a remote-control-operated Whoopee Cushion in his sleeping bag. According to Cuarón, Daniel tried really hard to stay in character while everyone else was laughing.
Two Persian red cats were used for the role of Crookshanks: Crackerjack and Pumpkin
Much of the filming was done in Scotland, so the filmmakers wanted to be sure that a Highland Cow, a breed of cattle native to Scotland, appeared in the film. The large, hairy animal with big horns can be seen in front of a shop in Hogsmeade when Ron and Hermione go and look for Harry after he leaves the pub.
Among the difficulties associated with filming in Scotland was the amount of rain that fell during the shoot. During the breaks in filming, helicopters delivered large bags of gravel to the set in order to prevent it from washing out. Many of the filmmakers were concerned as to how this would affect the look of the film, although director Alfonso Cuarón and cinematographer Michael Seresin insisted that it was the best look that they could have come up with.
A clause in Alfonso Cuarón's contract forbade the director from cursing in front of the kids on set.
In order to acquaint himself with his three lead actors, director Alfonso Cuarón had each of them write an essay about their characters, from a first-person point of view. Emma Watson, in true Hermione fashion, went a little overboard and wrote a 16-page essay. Daniel Radcliffe wrote a simple one-page summary, and Rupert Grint never even turned his in.
Cinematographer Emmanuel Lubezki (frequent collaborator of director Alfonso Cuarón) was supposed to be working on this film, but due to scheduling conflicts he was replaced by Michael Seresin.
The symbols under Sirius Black's picture on the Wanted Poster translate as "more or less human."
An additional set was built for the candy shop: the cellar. Not used in the film, it was included in a special feature on the DVD release that allowed viewers to explore the shop.
Subplot involving the Sneakoscope concept from the novel, as well as an attempted attack on Ron in his sleep at Hogwarts by Sirius Black, were filmed (and can be partially found as additional scenes on some DVD versions) but ultimately scrapped from the finished version. Oddly enough, a small bit from the latter, Harry's lines about missing a chance to capture Black, was still featured prominently in most promotional trailers. (Source: 2-Disc DVD extras & trailers).
After the death of Richard Harris, many actors were considered for the vacant role of Albus Dumbledore. Christopher Lee was in the frame for a while, and there was a rumor (reported in many newspapers) that Ian McKellen was also considered. The Harris family wanted Richard's longtime friend and peer Peter O'Toole for the role but there were studio concerns over insuring O'Toole for the remaining five films. Richard Attenborough also lobbied for the role but was ultimately turned down.
This film actually marks the second time that Michael Gambon has replaced Richard Harris. Harris had previously played Inspector Jules Maigret in Maigret, while Gambon took over the role in the television series Maigret.
Gary Oldman and Timothy Spall have both played the William Shakespeare-created character of Rosencrantz; Oldman in Rosencrantz & Guildenstern Are Dead and Spall in Hamlet.
The script for this film makes no mention of Professor Flitwick. Wanting to keep Warwick Davis involved, director Alfonso Cuarón came up with the idea of having him play the choir director. In the next film, Mike Newell liked the look of the choir director and wanted to keep using it. Therefore, the choir director became Flitwick, and his new look has been used for all the subsequent films.
As part of a promotion by the toy company LEGO, in the United States, some cinemas handed out free mini-knight bus LEGO kits with the purchase of a ticket.
The last Harry Potter film to be released on VHS.
First film in the franchise to have rainy scenes at Hogwarts.
Last film in the series to be dubbed into Icelandic.
Although most of the Hogwarts scenes were filmed on studio sets (unlike the previous films which were shot largely on location), the geometric staircase at St. Paul's Cathedral, London, was used as the staircase that leads to the Divination classroom.
Dawn French, who plays the Fat Lady in this film (but not in Harry Potter and the Sorcerer's Stone) is the wife of Lenny Henry, who voiced the shrunken head on the Knight Bus.
The design of the large clock which functions as a visual motif in this film appears to be based on the Old Town Clock (also called the "Orloj" - pronounced "OR-LOY") in Prague, Czech Republic. The Orloj tells not only the time, but shows the month, the sign of the Zodiac, and shows the relative positions of the moon and sun.
Michael Gambon admitted later on that he saw "no point" in reading the books, so during the whole course of playing the role of Dumbledore, he never read any of them.
Ron's fear of spiders was explained by author J.K. Rowling as stemming from an early trauma, when his practical joker brothers, Fred and George, tormented him with spiders during his infancy.
The Hufflepuff Seeker whom Harry competes against during the Quidditch match is Cedric Diggory. Diggory is his rival again a year later during the Tri-Wizard Tournament.
Two actresses in the film have played the Greek goddess Thetis: Dame Maggie Smith in Clash of the Titans and Julie Christie in Troy.
The lyrics to the song playing in the opening feast at Hogwarts come from William Shakespeare's famous play Macbeth. The lines in the play are spoken by witches, who are called the "Weird Sisters". In the novels, the Weird Sisters are a popular wizarding band.
It was Alfonso Cuarón's idea to have a Hogwarts Choir singing as the students enter the school, and he suggested using "Double, Double Toil and Trouble" from William Shakespeare's Macbeth. John Williams agreed, so the tune - and lyrics - ended up being used throughout the film, titled "Double Trouble". The Shakespeare/Macbeth motif went so far that that the film was marketed under the tagline "Something wicked this way comes".
The Dursleys have three television sets in their house; one in the living room, one near the dining table, and one in the sunroom. While not mentioned in the film, it is explained in the book that Dudley complains about the long walk from the fridge to the television in the living room.
The only Harry Potter film not to gross over $800 million worldwide.
Ian Brown: the singer (formerly of The Stone Roses) appears briefly in the bar at the start of the movie reading "A Brief History of Time" by Stephen Hawking. He was originally cast as the pub landlord, but the role was cut right down due to timing issues.
Annalisa Bugliani, Tess Bu Cuarón: Director Alfonso Cuarón's wife and their daughter are the mother and baby in the portrait next to the Fat Lady.
Alfonso Cuarón plays the man seated holding two lit candles when Harry enters Madame Rosmerta's Tavern.
The ending of the film, in which Sirius escapes on Hagrid's hippogriff, is actually a reversal of the opening of Harry Potter and the Sorcerer's Stone, in which Hagrid arrives on a flying motorcycle which, the book reveals, he borrowed from Sirius.
Despite featuring the idea of a mass murder as the back story, this is *arguably* the only book/movie in the series where no person dies in the story itself. The argument is that, while the villain in Harry Potter and the Chamber of Secrets was destroyed, he was a ghostly automaton who was, perhaps, never alive to begin with.
Early in the film, Harry sees a newspaper article with a photograph of the Weasley family in Egypt. Though it is never again mentioned, this is a very important plot point in the book. While on an inspection of Azkaban the Minister of Magic had a copy of that paper, and gave it to Sirius Black who recognized Peter Pettigrew disguised as Scabbers. This is what made him decide to break out of Azkaban, track down Scabbers at Hogwarts, and take his revenge by killing him.
Lupin says that he was very close with Harry's mother. This may seem at odds with the book's story that Lily Evans was a close friend of Lupin's rival Severus Snape. However, J.K. Rowling revealed that after graduating from Hogwarts, Lupin still found it difficult to find paying work, because nobody wanted to employ a werewolf. James and Lily, therefore, financially supported him.
Harry discovers that Sirius Black is his Godfather. Author J.K. Rowling had two Godfathers, named Stanley and Ernie. These names are used for the conductor and driver of the Knight Bus early in the film.
After the Fat Lady reports that Sirius Black is in the castle, there's a short scene of the large front gate closing up. As it does, you see a full moon in the sky and hear Lupin's wolf-form howling.
Although the Marauders' Map, created by Masters Moony, Padfoot, Prongs, and Wormtail plays a large part in the film, the identities of the first three are not made clear. This is surprising as this was important to understanding this plot in the book. Moony was Lupin, who was supported by his three friends. These learned "Animagus" shape shifting techniques to sympathize with him. James Potter was Prongs the Stag (a trait passed on to the Patronus of his son Harry), Sirius Black was Padfoot the Dog, and Peter Pettigrew was, more obviously, Wormtail the Rat.