This story is a sequel to G5 Adventures in The Great Mouse Detective
A few weeks after returning from their last Unity Quest in London, the ponies have been preparing for the Nightmare Night party in Zephyr Heights, but when the big night finally arrives, they are summoned away to the mortal world on Halloween night, where the Mane 6 reunite with their Mystery Incorporated friends for a night of spookiness and fun.
The Amazing Krudsky, a failed carnival magician, steals the light magic from Fairy Princess Willow, it's up to the Mane 6, Shaggy and Scooby to stop him, or else the mortal world will be turned into Halloween monsters for all eternity!
Our heroes board the Grim Reaper Railroad into a fantastical Halloween realm where they encounter real monsters, flying brooms, talking jack o'lanterns and magic fairies, all in a quest to reach the Goblin King's castle to retrieve the Goblin Scepter before midnight, with help from some brand-new friends, including Mystique Blaze, a young earth pony who has the supernatural ability to control fire.
But will the Mane 6, Shaggy and Scooby succeed in their plans to save their friends and the mortal world they know and love? Or will Krudsky succeed in his dark schemes of world domination?
Get ready for the ride of your afterlives as you stay tuned for this monstrous, music-filled Halloween adventure, filled with the true meaning of courage and friendship!
(S2E7 of G5 Adventures)