As the annual Black Gathering, an airship race sponsored by mafia organisations, is held, they participate on Saint's orders with Impey's rebuilt aircraft, hoping to get a clue by winning the competition and subsequently its rumoured grand prize: the posthumous writings of Isaac. However, work on it only finishes that very day, causing them to barely catch the race start time. Participating alongside him is an eccentric scientist named Nemo who declared Victor as his rival when they were both serving in the royal court...