The series, described as a dark adult drama which mixes multiple genres, is set in the sleepy Arctic town of Fortitude, whose close-knit community is shaken up by the brutal murder of a British research scientist. Leading the investigation is local Sheriff Dan Anderssen, who is joined by British detective DCI Milton Caldwell.

Beneath the depths of the Arctic ocean a submarine and its crew are stuck under ice. With no power, limited oxygen and no communication with the surface how will they survive?