Double, Double, Toil and Trouble

Kelly and Lynn Farmer learn that their parents, Don and Christine, are deeply in debt and risk losing their home. The family visits Christine's Aunt Agatha to ask for a loan, but she immediately refuses help, setting the stage for the family's struggles.

The girls meet Aunt Agatha's grave digger who recounts the history of their home, once belonging to a powerful witch. He tells them about the moonstone hidden inside the house, which grants magical power and the history of Agatha's twin sister Sophia, who was banished into a mirror.

The digger explains that Agatha cast a spell trapping her sister Sophia in a mirror, and that on Halloween, at midnight, the spell will become permanent unless broken by twins possessing the moonstone. The girls decide to rescue Aunt Sophia before it's too late.

Kelly and Lynn learn that Aunt Agatha always wears the moonstone around her neck, making it difficult to steal. They switch costumes with other trick-or-treaters to sneak out and seek help, carrying a magical toy wand as their guide.

The girls meet Mr. N, a homeless man who offers assistance, and visit a psychic to find the witches' gathering. Using the magical wand, they locate the gathering site near the woods and head toward it, with Oscar the dwarf agreeing to help them.

The girls arrive at the witches' gathering in costumes and witness Aunt Agatha revealing her story of the spell cast on her sister. Aunt Agatha plans to gain more power by stealing the moonstone from her own home, leading to chaos and pursuit through town.

Lynn and Oscar head towards Aunt Agatha's house with the moonstone, while Kelly joins Mr. N in a confrontation. Aunt Agatha and her butler follow, leading to chase scenes in abandoned locations and townsides, with Mr. N turning into a crow to fight her magic.

Lynn finds Aunt Sophia trapped in the attic, and Kelly escapes from George. The group, now split, races against time to find the mirror where Sophia is held. Lynn promises to help Sophia and refuses to betray her sister, strengthening their bond.

With moments left before midnight, Lynn and Kelly, united in love and courage, ask Aunt Sophia for the incantation to break the spell. Aunt Agatha tries to stop them but ultimately falls into her own mirror, which shatters, trapping her in the netherworld forever.

Aunt Sophia is freed and returns to her family, who celebrate their victory. The twins are praised for their bravery, and Aunt Sophia and George redecorate the mansion, promising a new start. The family happily moves forward, thankful for the magic family bond.

While cleaning the attic, the twins see Aunt Agatha's face in a broken mirror shard, pleading for help. They refuse her request, symbolizing their full victory over her evil, and walk away holding hands with the magic wand, ending the story.