About the book: year / The action of the adventure novel by writer M. P. Belov takes place on the Island of the Seven Winds, in the reserve of the most valuable sea fur-bearing animal - the sea otter. Mysterious events take place on the island: sea otters begin to mysteriously disappear under water, and sometimes this happens before people’s eyes. Young sailor Maxim Parygin, an underwater swimmer, discovers a “black shark”. It is she who attacks defenseless sea otters, carrying them somewhere into the depths of the ocean. But the “shark” turns out to be a complex cybernetic device created by a prominent Soviet scientist Kovalev and stolen by criminals…