The Happiness Patrol: Part One

The Doctor and Ace arrive on the earth colony of Terra Alpha, a colony that is under the misguided dictatorship of Helen A. On Terra Alpha, sadness and misery are capital crimes, and "killjoys' (anyone who does not adhere to these strict laws) are executed on the spot by Helen A's secret police, a motley crew of female assassins known only as "The Happiness Patrol".