No Século XIII, o sinistro príncipe Prospero (Vincent Price) vive afastado do mundo, enclausurado em seu castelo, enquanto a temível Peste Vermelha toma conta do resto da cidade. As injustiças do monarca serão vingadas durante um baile à fantasia realizado no interior do seu castelo, quando uma misteriosa figura vestida com uma máscara vermelha revela sua identidade.
Deborah and Charles, young executives at the thriving Pontifex Advertising Agency, are very much in love. Deborah is recognised by her employers as the most brilliant TV executive in the country, while Charles is regarded as 'thoroughly reliable'. But there is one hard-and-fast rule at the agency: the board of directors will not allow any married women on their staff; as soon as a girl marries, she must resign!