Agatha Cromwell's History
Pre-Series
During the Dark Times, 18-year-old Splendora Agatha Cromwell was the Princess of Halloweentown, who possessed an ancient power known as The Gift. It was a necklace that had great power to give the wearer complete control over any person, which was passed down to all the witches in the Cromwell family since the time of it's creation, - but it could only be worn by a Cromwell witch. An evil battalion of dark warlocks and witches known as The Dominion, sought The Gift and wanted Splendora to use it to dominate Halloweentown. Wanting to live like a regular witch, Splendora placed The Gift in a chest and hid it under the ruins of Witch University, and it is said that only her heir could unleash The Gift that's stored inside the box and use the power within it.
Halloweentown
On Halloween night, Aggie goes on her yearly visit to Earth, to see her daughter and grandchildren, as it is the only night the portal between Halloweentown and Earth is open. However, Aggie's grandchildren do not know of her true heritage or her magic. Aggie entertains her grandchildren with tales of Halloweentown, which they believe to be fictional.
However, after they are in bed, Aggie has a discussion with Gwen about Marnie. Having celebrated her thirteenth Halloween, Marnie must begin training immediately or her ability to perform magic could be lost. Aggie asks for Gwen and the children to come to Halloweentown with her. Aggie then reveals that strange events have been happening in Halloweentown, and that her real reason for coming is that she needs Gwen's assistance. Citizens have been disappearing under mysterious circumstances. However, Gwen refuses, preferring that her children live a normal human life. Unknown to either, Marnie had been eavesdropping, and immediately begins plotting with her siblings to follow Aggie to Halloweentown.
Aggie then returns to Halloweentown unaware of the children stowing away. Returning home, Agatha begins to prepare a witch's brew, with the goal of lighting a magical talisman known as Merlin's Talisman that should be able to fix the mysterious happenings in Halloweentown. During this time, Aggie's grandchildren arrive. Against her better judgment, Aggie decides to let them stay. When the witch's brew fails, due to being instant, Aggie takes the children into town to gather ingredients for a new batch. While there, Aggie takes Marnie to a broom shop and buys her a broom, teaching her the basics of performing magic. However, Gwen, having discovered her children's disappearance, arrives and prepares to take her children home.
Meanwhile, Luke, a young goblin, offers to take Agatha to an old theatre. Gwen and the children notice this and decide to follow her, sensing trouble. In the theatre, Aggie is confronted by a shadowy demon, who attempts to attack her. Aggie dodges easily, but when Gwen attempts to come to help and is hit, Agatha is distracted long enough to be stricken. Aggie quickly reveals to Marnie and her siblings that the spell will freeze them both, and orders them to flee.
While Aggie is frozen, Marnie and her siblings work to complete the Talisman. Stumped on what to do with it, Marnie remembers a statement of Aggie's and installs it in a jack-o-lantern in the center of town, despite the arrival of the shadow demon. The talisman reverses the freezing spell, and Aggie and Gwen arrive to learn that the shadow demon is none other than Kalabar, the mayor of Halloweentown. Aggie and Gwen attempt to work together to defeat Kalabar, but only the combined magic of the entire Cromwell family is enough to defeat him.
Gwen and the children prepare to return to Earth. However, Gwen reveals her intention to help train Marnie, and invites Aggie to live with them. Aggie happily accepts. Aggie and her familybus and prepared to head to the mortal world. Aggie and Marnie sat beside each other and waved a happy goodbye to the citizens of Halloweentown and with the help of Luke, the new bus driver, they blasted off into the sky and were headed to the mortal world.
Halloweentown II: Kalabar's Revenge
Aggie now lives on Earth with her daughter and grandchildren, helping to train them in magic. However, Gwen places certain restrictions on Aggie's ability to openly perform magic, and so she keeps her magical items in a hidden room in the house. On Halloween night, Aggie helps host a Halloween party for the neighborhood. During this time, Aggie's spell book is stolen by a young man named Kal, who manipulates Marnie into revealing it.
After discovering the stolen book, Aggie and Marnie travel to Halloweentown to search for it. Once there, they learned that Kal is actually the son of the deceased Kalabar, and intends to avenge his father. Upon arriving in Halloweentown, the two discover that the town is under the effects of The Gray Spell, which turns the whole town into a black and white version of itself while its residents have been turned into boring human stereotypes. Aggie attempts to find the spare copy of her spell book, but after realizing that it is lost, she and Marnie travel to Gort, whose home contains all lost items from both worlds. While searching for it, Aggie falls under the Grey Spell's influence, and begins mindlessly sorting socks.
Aggie is later returned to normal by Marnie, who had discovered the reversal spell after traveling back in time. However, Marnie has returned too late to travel back to the mortal world as the portal between the worlds is only open on Halloween night until midnight, making it difficult for her to stop Kal, who plans to use The Creature Spell in the Mortal World at midnight to turn humans into the monsters they were mocking. Aggie attempts to console her granddaughter by promising to train her to take on Kal over the next year. Instead, Marnie joins forces with her siblings to open the portal by force. Both Aggie and Marnie return to the mortal world, where Kal is defeated. With the ability to travel freely between the mortal world and Halloweentown, Aggie helps her family undo the Grey Spell's damage.
Halloweentown High
Three years after the previous film, Aggie assists Marnie in guiding a group of disguised Halloweentown citizens in integrating on earth. Marnie had asked The Halloweentown Council to work towards openness between the two worlds, but had mistakenly bet her family's magic that it could be done. In order to help, Aggie serves as a substitute teacher in the local school, but keeps having problems with using magic. She also begins a relationship with the school principal, Phil Flanagan. Unknown to her, Flanagan is the last member of the Knights of the Iron Dagger, who historically persecuted creatures. Aggie helps Marnie in helping the disguised creatures adjust, but is troubled by attempts to attack/reveal them.
Eventually, Aggie and Marnie learn that one of the members of The Halloweentown Council, Edgar Dalloway, had incited the attacks to cause Marnie's project to fail and claim the Cromwell magic for himself. After the Halloweentown citizens are revealed during a carnival, Dalloway steals Marnie and Aggie's magic for himself. Luckily, however, Gwen arrives, having told the rest of the council the entire thing. The Cromwell Magic is returned and Dalloway is imprisoned in Aggie's Witches' Glass. In addition, the town comes to accept the people of Halloweentown and Aggie's status as a witch is accepted by Flanagan, who renounces his membership as a Knight.
