In the winter of 1969, the bodies of four young women were discovered in a cemetery near the tip of Cape Cod. In a place once known as Helltown, the victims had been shot, stabbed, dismembered and mutilated. As investigators would soon learn, the perpetrator was a young, handsome serial killer named Tony Costa. A bizarre former taxidermist with a split personality and penchant for violence, Costa ultimately mobilized friends in the hippie community for support and retribution, and captivated literary icons and rivals Kurt Vonnegut and Norman Mailer. Costa embarked on a daring cat-and-mouse game with investigators, who --- as the body count kept growing --- were desperate to put an end to the killing season on Cape Cod.