In the remote Arctic town of Fortitude, two children make a remarkable find; and later, a horrific crime is discovered.

Vincent is arrested for the murder, but a new arrival in Fortitude gives Sheriff Anderssen something else to think about.

The police are closing in on their prime suspect for the killing, but Ronnie Morgan is acting suspiciously…

Dan and Frank travel up the coast in search of a suspect, but Dan’s feelings for Elena are threatening to overwhelm him.

The evidence against Frank looks overwhelming, but Elena's past is about to catch up with her…

A shocking discovery threatens to tear the Sutter family apart.

After the awful discovery of Liam's guilt, Fortitude tries to move on; but there is more horror in store…

Another murder has shaken the town, but this time the identity of the killer seems obvious. Can things really be so simple?

Frank takes the law into his own hands. Meanwhile, DCI Morton is closing in on the truth about Pettigrew's death.

Vincent and Natalie are forced to question their own ethics. Meanwhile, Morton gets a surprise that may turn out to be his last.

Dan has an emotional encounter with Morton. Meanwhile, Vincent has a brainwave which will lead him into danger.

The horrifying truth about the murders is revealed.