Three months have passed since Makar Ilyushin disappeared during an investigation in an old mansion, and Sergey Babkin has fallen into depression. To help her husband, Masha books two places on the brigantine "Dream" for a two-week voyage through the seas of Greece. On board, besides them, there will be six more tourists—and at first everything goes well. However, strange and ominous events soon begin: the director is pushed overboard, young Stefan is dragged under, and Vladimir Rudenko is caught in a rockslide. Sergey Babkin will have to find out who will be the next victim, and whether a sea devil truly stands behind it all. Can he handle it without Ilyushin’s help?