Pocho Martin's body was discovered on the beach of a fishing village. Pocho has been assassinated, according to the forensic Ramiro, which alerts Commissioner Carlos. Pocho's friend, young Silvia, receives the sad news but is more concerned about her impending wedding with Andy. Oscar, the crackpot, tells Carlos about the dangerous sirens of Deer Island, evil women who lure sailors and kill them. When Ramiro and Carlos arrive on the island, they meet the sisters Lila and Mary, who run a tavern/brothel near the beach. Carlos and Lila are old friends who are happy to see each other again, but Pocho's murder remains unsolved.