Murder investigator Evert Bäckström is convinced that crimes have been committed when a women's cranium is found on an island in the archipelago. But his investigation is countered by the police chief and when the woman's identity is clarified, the entire investigation is turned upside down.

Park manager Fiona is tasked with taking care of some former friends who won an exclusive private sneak preview of Halloween at Liseberg – a whole night, all alone in the empty park. But cotton candy, lovely rides and lots of laughter soon turn into something completely different, as they realize they are not alone in the park. And the night of dreams quickly turns into a true nightmare.