It was a strange vacation for Katya Petrovskaya, an employee of the press center of the Internal Affairs Directorate. Together with her husband Vadim Kravchenko and their friend Sergei Meshchersky, they arrived at the Baltic resort and on the very first day they witnessed a ferocious and mysterious murder. The matter did not stop there - a few days later a teenage girl was found dead. As Katya found out, such “incidents” with young girls are not new here. But the killer is like a ghost, he leaves no evidence, and then there are local legends about Vodyanoy, who takes revenge on people; his wet footprints are regularly found on the floor of the church. Three people at once - Katya, Meshchersky and local resident Marta - identified the killer. Only Meshchersky at the moment of inspiration was fishing in the sea, and Katya and Marta found themselves face to face with a maddened maniac.