In Italy in the 1930s, sky pirates in biplanes terrorize wealthy cruise ships as they sail the Adriatic Sea. The only pilot brave enough to stop the scourge is the mysterious Porco Rosso, a former World War I flying ace who was somehow turned into a pig during the war. As he prepares to battle the pirate crew's American ace, Porco Rosso enlists the help of spunky girl mechanic Fio Piccolo and his longtime friend Madame Gina.

Sophie, a young milliner, is turned into an elderly woman by a witch who enters her shop and curses her. She encounters a wizard named Howl and gets caught up in his resistance to fighting for the king.