The exploration ship Rush, with a crew of 150 intelligent dolphins, 7 humans and one intelligent chimpanzee, finds an abandoned fleet of spaceships - each the size of a small moon. Perhaps they belong to the Progenitors, the legendary alien race that first began to sow intelligence among the stars, and then disappeared without a trace. Possessing information about one of the most important discoveries in the galaxy, the "Throw" becomes a target for several fleets of extraterrestrial civilizations and crashes on an unknown water planet Kitrup. While alien armadas in space are waging a real war in the struggle for the knowledge of the Progenitors, the crew of the "Throw" finds out that Kitrup is a very strange world. Its fauna is extremely hostile, and in its endless depths there are many secrets that could change the history of the entire inhabited space forever.