Only by a miracle can the spacecraft “Pericle” manage an emergency landing, having returned from a research expedition to Jupiter. On the way home, an unknown illness strikes the entire crew. In the hands of Sam Bertolli, the emergency service doctor—formerly a captain in the mobile forces— the last surviving astronaut dies, managing to say only two words: “ship” and “danger.” Will Sam be able to decipher what lies behind these words, when the future of human civilization is at stake?