Perry Rhodan has discovered a huge space ship, an ark in space, carrying a population of humans who set out on their journey 55,000 years ago, from Earth - Lemurians, the legendary forefathers of mankind. A new onslaught of the Beasts is imminent. These organic killing machines have learned about the arks and used them - unnoticed by their inhabitants - for their own purposes. Meanwhile Levian Parron sets out to go back in time to undo the onslaught, including 55,000 years of history. Only Perry Rhodan can stop the Beasts as well as Levian Parron ...