Every year, a ship with black sails visits the city of Athens. Fourteen young people are chosen to go to the island of Crete, but they never return. One year, prince Theseus is determined to travel with them and defeat the Cretans' fearsome monster, the Minotaur. He is helped by the princess Ariadne, and they escape from the island - but on their return, Theseus makes a terrible mistake.