In the summer of 1978, the Rolling Stones begin their US tour, David Berkowitz (aka the Son of Sam) is sentenced to 365 years in prison, and Grease reaches number one at the box office. But for the residents of Bowie, Maryland, those stories are all second string. For them it is the summer of the Goatman.

Fifteen-year-old Chris Dwyer and his friends have their summer all planned out with marathons of Atari and Dungeons and Dragons, interrupted only long enough to cool off at the local pool and possibly catch a glimpse of Melissa Casey in her pink bikini. But when reports of headless bodies surface on the evening news and a mysterious horned creature begins stalking Chris, plans change. He soon discovers his pursuer is none other than the legendary Goatman, a creature so terrifying and vicious it rips its victims apart with its bare hands. But what does it want with Chris?

With his friends and brother by his side, Chris dives deep into the dark history of his hometown, uncovering a hidden world of witchcraft and demons. He hopes to discover the creature's origin and a means to stop its murderous rampage, but what he stumbles upon chills his very soul and causes him to question whether any of them will survive when the Goatman comes knocking.