About the book: year / Summer. Two friends come to vacation in a town on the Black Sea coast: cheerful, lively Tatyana and timid, shy Zina. By chance, in one of the houses they find the body of a strangled woman, and they pick up a black cell phone from the floor, in which a funeral march sounds and a rude voice orders the receiver to be returned through the security guard of the Brigantine club. The requirement has been fulfilled, and now you can forget about the troubles and enjoy the delights of a resort holiday. But, oh, horror! The same mournful melody is heard from the cell phone of a new acquaintance. Since then, a series of troubles have haunted the friends. They should contact the police, but they are not looking for easy ways. Now revealing all the secrets is a matter of principle, and nothing can stop two home-grown detectives on this path: neither threats, nor a pre-trial detention cell, and even kidnapping and attempted murder. After all, everyone knows: the secret always becomes clear…