Surrounded by the savage beauty of the frozen landscape, Fortitude, a small town in the Arctic Circle, is one of the safest towns on Earth. There has never been a violent crime here. Until now.
In this close-knit community, a murder touches everyone and the unsettling horror of the crime threatens the future of the town itself. The local police chief, Sheriff Dan Anderssen (Richard Dormer), must investigate alongside Eugene Morton (Stanley Tucci), a detective who has flown into Fortitude so fast that questions are being asked about how much he knew, and when. As the two cops try to make sense of the killing, each finds reasons to mistrust and suspect the other.
The murder is a catastrophe for the town's governor, Hildur Odegard (Sofie Grabol), who's planning on turning the declining mining town into a site for high-end tourism. Meanwhile, for wildlife photographer Henry Tyson (Michael Gambon), who only has weeks left to live, the murder is the catalyst to unearthing Fortitude's darkest secret. As the cold Arctic darkness gives way to endless summer nights, this apparently idyllic community struggles to make sense of the murderous horror that has been let loose in its heart.