Pirates! is an adaptation of the operetta, The Pirates of Penzance, without the music.
On turning 21, Frederic is released from his apprenticeship with a band of soft-hearted pirates. He hears a chorus of girls and falls instantly in love with Mabel, the daughter of Major General Stanley. The pirates enter the scene and are confronted by the major general, and when he tries to divert them with a lie, they assault his house. A melee ensues, which is quashed by a comic band of policemen. More complications abound when Frederic learns that, because he was born on Leap Day (Feb. 29), a day that occurs every four years, he has had far fewer birthdays and is still indentured to the pirates!