Scooby-Doo! and the Goblin King

Mystery Inc. attends the Coolsville Halloween carnival and encounters the Amazing Krudsky. Krudsky refuses Scooby-Doo access to his latest show after Scooby allegedly causes an accident, triggering a public confrontation. The gang exposes Krudsky as a fraud, and he swears revenge as they are thrown out of the carnival. Despite the setback, they decide to go trick-or-treating anyway.

At Krudsky's tent, Fairy Princess Willow reveals the existence of the Goblin Scepter and hints at its world-changing power. Krudsky vows to find the scepter and use it to take over the world. Willow tries to stop him but knocks herself out, allowing Krudsky to capture her and absorb her magic, becoming a real magician.

Shaggy and Scooby stumble upon a genuine magic shoppe while trick-or-treating. Mr. Gibbles reveals to them that magic is real, not merely showmanship. Krudsky interrupts, recapturing Willow, and turns Gibbles into a rabbit while stealing his magical equipment before leaving.

Gibbles urges Shaggy and Scooby to stop Krudsky. He grants them monstrous disguises and sends them on a train to the spirit world, warning that they must return before sunrise or be trapped there forever. The journey marks the start of their perilous quest.

Shaggy and Scooby arrive in the spirit world and struggle to locate the Goblin King's owner. Jack O'Lantern directs them to the Grand Witch, who lends them her flying broom named Broomy to reach the Goblin King's castle. After crash-landing in a fairy village outside the castle, they are aided by friendly fairies who guide them toward the castle entrance.

Disguises provided by the Grand Witch help Shaggy and Scooby infiltrate the Goblin King's castle, but the disguises wear off and they are captured and sent to the dungeon. They are ultimately rescued by Jack, the fairies, and Broomy, who come to their aid. The rescue reopens their path to confront Krudsky's plan from within the fortress.

Back in the mortal realm, Krudsky negotiates with the Goblin King to trade Willow for the Goblin Scepter at midnight. Velma struggles to comprehend the bizarre events, while Fred and Daphne begin to formulate a plan to stop the trade. The tension builds as the clock ticks toward the exchange.

Mystery Inc. locates Krudsky and the Goblin King, but they can only capture the Goblin King before Krudsky claims the scepter. Krudsky uses the scepter to unleash an army of goblins, threatening to conquer the world and turning some people into monsters, including Velma, Fred, and Daphne. The heroes scramble to respond as chaos spreads.

Shaggy, Scooby, Jack, and Broomy arrive to intervene. Jack sacrifices himself to defeat Krudsky, while Scooby grabs the scepter and uses its magic to break Krudsky's spells. Scooby then returns the scepter to the Goblin King to restore balance.

The Goblin King grounds Willow for causing the mayhem, and helps Gibbles resurrect Jack. He takes Krudsky prisoner and returns his army, Willow, Jack, Broomy, and Gibbles to the spirit world. He erases Fred, Daphne, and Velma's memories to keep his world safe, while allowing Shaggy and Scooby to keep theirs for their courage.