Alongside his father, Prince Argai fights the barbarians of Queen Oriale; the prince has a book of prophecies in which his fate seems to be transcribed; by following the book to the letter, the prince finds himself projected in New York in 2075.

The masked man witnesses the arrival of Prince Argai in New York; detectives look for this strange man, whom they must find before the militia.

The Pasha is an old friend of Oscar, who reigns over the New York underworld; he will not only donate false papers to Prince Argai, but also puts his best pilot at his service to take him to the Rebel planet.

While being chased by the Black Guard, Prince Argai and his acolytes are aided by Princess Lorelei's hunters; the latter provides them with access maps to the F-107 prison so that they can free Oscar.

Argai and his friends go to Tirloch in 1250; while in the monastery, they learn of the departure of Father Grégoire for Paris, who took one of the books of prophecy with him.

Prince Argai learns that behind each of the quatrains of the book of prophecies hides one of the ingredients of the antidote, which will make it possible to cancel the evil spell on Angela.