Somewhere outside space and time there waits the Celestial Toymaker, an enigmatic being who ensnares unwary travelers into his domain to play out his dark and deadly games. Separated from the security of the TARDIS, the Doctor is forced to play the complex trilogic game with evil magician. Meanwhile, Dodo and Steven must enter into a series of tests with, among others, the schoolboy Cyril and the King and Queen of Hearts. If they lose, they are condemned to become the Toymaker's playthings for all eternity. For in the malevolent wonderland that is the Celestial Toyroom, nothing is just for fun...