The head of Galaxity's Spatio-TemporalService himself has joined Valerian and Laureline at Inverloch Castle. There,among various human and alien allies, he explains to them the threat that loomsover Earth: all of the recent incidents, all those important people gone madand threatening to bring about the apocalypse...All of that is due to themalicious influence of the mysterious planet Hypsis. But Hypsis is a world thatmoves from system to system - it'll need to be pinpointed first...