In the conclusion of the four-part story "The Celestial Toymaker," the title character (Michael Gough) tries to lead "human pawns" Steven (Peter Purves) and Dodo (Jackie Lane) astray with the help of his gregarious henchman, Cyril (Peter Stephens). As for the Doctor (William Hartnell), he must find a way to beat the Toymaker at his own game if he wants to reclaim possession of the TARDIS and escape the villain's weird domain. Fortunately, tricky though the Toymaker may be, the Doctor still has an ace or two up his sleeve. Written by Brian Hayles, "The Final Test" first aired on April 23, 1966. ~ Hal Erickson, Rovi