Afanasy Karachaev is found dead in his apartment. The official cause of death is heart failure, but Lya—who loved Karachaev—doesn’t believe this conclusion. She turns to a private detective, Alexey Kisanov, who takes the case. Very soon it becomes clear that Karachaev was helped to go to the other world. But that was the first and last clear point in the matter—after that, only riddles remained. In the most mysterious way, Afanasy Karachaev’s daughter disappears, and the detective searches for her traces in the dark waters of the Moscow Sea. The theories multiply like molecules in organic chemistry: inheritance? Business interests? Revenge from a cast-off lover? Never before had Alexey Kisanov faced such a murky case! The solution will shine through only at the very end…