In the middle of abandoned Swedish swamps is the village of Mossmarken, where people have come since ancient times to leave offerings to the gods. The village is fraught with terrible secrets, because for many years local residents have disappeared in the ominous swamps of Mossmarken. They were found a few years later with a bag of coins in their pocket. Young biologist Natalie Strom, for the sake of research for her dissertation, returns to her once native place, where she left after a terrible family tragedy. There she meets Johannes, a local college student. One night, after a storm, she finds her new friend unconscious in a swamp, and in his pocket is a scattering of gold coins, next to a fresh grave. This discovery provides a frightening reason to begin researching the past - how for the police and for Natalie. Is the swamp thirsty for new victims, as local residents claim? Or is the terrible evil that lurks in this small village human in nature?