The TARDIS arrives on the planet Terra Alpha, where the Seventh Doctor and Ace discover a society in which sadness is against the law - a law enforced zealously by the brightly uniformed Happiness Patrol. The planet is ruled by Helen A with the aid of her companion, Joseph C, and her carnivorous pet Stigorax, Fifi.
Sylvester McCoy
as The Doctor
Sophie Aldred
as Ace
Sheila Hancock
as Helen A
Ronald Fraser
as Joseph C
Georgina Hale
as Daisy K
Harold Innocent
as Gilbert M
Lesley Dunlop
as Susan Q
Rachel Bell
as Priscilla P
Jonathan Burn
as Silas P
Tim Barker
as Harold V
David John Pope
as The Kandyman
John Normington
as Trevor Sigma
