After a mysterious encounter during World War I, famed flying ace Marco Rossellini was transformed to look like a pig. Now known as Porco Rosso ("Red Pig"), he works as a flying bounty hunter in his crimson seaplane, protecting ships from sky pirates. After a run-in with a band of pirates, Porco has his plane repaired, and his mechanic's granddaughter, Fio, becomes an unwitting pawn between Porco, the pirates, and Porco's girlfriend.