Halloweentown High (also known as Halloweentown III) is a 2004 Disney Channel Original Movie that premiered on Disney Channel on October 8, 2004 for the holiday of Halloween. This is the third installment in the Halloweentown series. It is also the last Halloweentown movie to feature Kimberly J. Brown as Marnie Piper and to have Sophie (Emily Roeske) in it.
Three years after the previous movie, 17-year-old Marnie Piper prepares to begin a new school year. She asks the Halloweentown Witches' Council to work toward openness between Halloweentown and the mortal world. She proposes to bring a group of Halloweentown students to her own high school in the mortal world. The Council agrees, but only after Marnie mistakenly bets "all the Cromwell magic" that her plan will work ("It was just a figure of speech!"). If she does not prove she is right by midnight on Halloween, her entire family will lose their magical abilities.
The Halloweentown students arrive, magically given human appearances to disguise their true non-human natures. School begins with Marnie acting as tour guide for the exchange group ("from Canada"), Aggie is substitute teaching so she can be available in case of need, a romantic interest in Marnie is shown by the new student Cody, and a possible threat to the school is coming from the Knights of the Iron Dagger. The Knights are a long-absent, anti-magic cult that wants to keep the mortal world closed off from Halloweentown.
While Aggie proves unable to teach any subject effectively (she keeps letting her magic take over: she conjures up a parrot in science class, and later we learn that a llama was produced, one kid was turned into a lamp post, and another lost one of their ears), the Halloweentown students keep to themselves, hiding in the refuge that Aggie magically creates for them in a remote student locker. Marnie gradually encourages the kids to join school activities and make new friends.
Marnie's progress is interrupted by a warning that appears to be from the Knights of the Iron Dagger, then by a magical incident at the mall that results in the Halloweentown students assuming their natural appearances (Marnie wonders what caused "that puff of smoke", but this is an error by the writers since the "puff" was really more like a huge purple lightning cloud), by a break-in at the secret magical locker, and finally by the disappearance of one of the students.
Meanwhile, Marnie's developing relationship with Cody parallels an unexpected romance beginning between Aggie and the school's principal, Phil Flanagan. Aggie suspects Cody of being the cause of the trouble, and tries to convince Marnie to halt their relationship, but Marnie in turn suspects Flanagan. They eventually discover that Phil is the Knight in question; he was told prior to the students' arrival that he was the last of the Order.
Edgar Dalloway, head of the Witches' Council and father of one of the students, Ethan Dalloway, is the real root of their problems. He wants to keep Halloweentown isolated from the mortal world, and used Flanagan to ensure the failure of Marnie's project. This, he hoped, would cause a negative reaction in Halloweentown and keep the portal between Halloweentown and the mortal world closed.
The Halloweentown students use the school's Halloween carnival to improve mortal attitudes toward magical folk. Their haunted house depicts the ordinary lives of creatures that have typically been seen as monsters in the mortal world, including displays like the "Monster Tea Party" and ogres "picnicking in their natural setting", and winds up boring the carnival goers. Gwen meanwhile uses a witch's glass to hunt down a missing student whom Dalloway imprisons.
At the school Halloween carnival, Edgar Dalloway launches magical attacks against mortal students by bringing the inanimate monsters in the haunted house to life. The ensuing damage and panic spiral beyond Marnie's and Aggie's ability to contain them, including a reanimated skeleton which grows 30 feet tall. Flanagan incites a mob to corner the Halloweentown students. Cody shames the crowd, the students reveal themselves, and the crowd accepts them for who they are. Flanagan also renounces being a knight and accepts Aggie.
Dalloway claims the Cromwell magic, but Gwen has shown the evening's events to the full Witches' Council. They return the Cromwell magic, Gwen returns with the student whom Dalloway had imprisoned, and the Council imprisons Dalloway in another witches glass (At this point the series diverges from real history quite dramatically, with the existence of Halloweentown and its inhabitants becoming known to the population of Earth).
The portal between Halloweentown and the mortal world opens in the middle of the haunted house, and crowds of kids from Halloweentown cross over to enjoy the carnival together with mortal world kids. Marnie flies off for a romantic broom ride with Cody and, while flying over the carnival, they kiss.
- In the movie there is a serious personality change in Gwen: in the first two movies, she does not like nor use magic, but in Halloweentown High she accepts magic and uses it often.
- Sophie appears only three times in the movie and does only simple magic.
- In Halloweentown II: Kalabar's Revenge, the family moved into a new house, and they appear in this film to have moved again, meaning that they have been in a different house in every movie.
- In Halloweentown II: Kalabar's Revenge, there was a door to Aggie's magical room that could disappear and reappear due to the magic of Aggie, Sophie, and Marnie. These rooms appear to be all part of a building, but can only be opened by magic. Yet, when Marnie tries to open an extra hallway, "she messes up the house". This power also explains the existence of the magical locker and the hallway leading to the council chamber.
- In Halloweentown II: Kalabar's Revenge, Luke mentioned that Kal (Kalabar's son) would be back, yet he has never been shown nor mentioned in this film and its 4th installment.
- This is Olesya Rulin's and Lucas Grabeel's first of four films together. The other films are High School Musical, High School Musical 2, and High School Musical 3: Senior Year.
- This is the only Halloweentown film where Halloweentown does not appear.
- Unlike the two previous movies, which occurred directly on Halloween and involved the antagonists wanting to takeover the mortal world. This movie and its 4th installment occur over the course of time leading up to Halloween and involve characters who seek to control.
- Ethan seems to have a crush on Marnie on the movie.
- This is Emily Roeske's last movie she appeared in to date.
- The high school scenes, shot mostly at Juan Diego High School in Salt Lake City, Utah had to be carefully staged. This private Catholic High School is, understandably, full of Christian artwork and statues, requiring hallway scenes to be full of wall "posters" to cover any religious prints or careful camera angles to avoid any religious statues in the alcoves.
- Kimberly J. Brown as Marnie Piper
- Debbie Reynolds as Splendora Agatha "Aggie" Cromwell
- Joey Zimmerman as Dylan Piper
- Emily Roeske as Sophie Piper
- Judith Hoag as Gwen Piper
- Lucas Grabeel as Ethan Dalloway
- Michael Flynn as Edgar Dalloway
- Finn Wittrock as Cody
- Eliana Reyes as Cassie
- Clifton Davis as Principal Flanagan
- Todd Michael Schwartzman as Pete the Werewolf
- Jessie Harward as Chester the Ogre
- Clayton Taylor as Chester's Human Disguise
- Olesya Rulin as Natalie, the Pink Troll
- Brent Johnson - Fire Juggler
- Darcie Johnson - Juggling Spectator