The chilling thriller concludes with a dramatic and emotional finale. Vincent faces a life-threatening situation, while Dan must make a devastating decision.

Dr Khatri attempts to cover her tracks when Michael presents the scientists with a miracle. Dan and Elena relive their trauma.

Michael finds something unexpected on the tundra, and Dan is confronted with what he is becoming, just as a heartbreaking discovery changes the town forever.

As the town attempts to come to terms with the recent tragedy, Petra and Ingrid seek the truth. Meanwhile, Dr Khatri moves a step closer to achieving her goal.

A disturbing challenge is issued. Michael finds a glimmer of hope for Freya, while Vincent's trust in Natalie is shattered.

DCI Morton pursues Henry Tyson into the Arctic wilderness in search of the truth, while worrying test results force Governor Odegard to take drastic action.

Panic sweeps through Fortitude as news of the second attack spreads. Dan and Morton must work together while Frank hopes the latest events will exonerate Liam.

In the penultimate episode, the truth about Billy Pettigrew is revealed. In the lab, Natalie and Vincent probe the cause of the disturbing events in Fortitude.

Michael sacrifices everything for a possible future with Elsa. As his violent deeds catch up with him, Dan realises he will never leave Fortitude.

In the remote Arctic town of Fortitude, two children make a remarkable find, while the discovery of a horrific crime brings a new arrival to the island that complicates Sheriff Dan Anderssen’s investigation.

Sheriff Anderssen and the police close in on their murder suspect, while DCI Morton follows a different line of enquiry.

Oslo sends two new officers to attempt to make some sense of the anarchy in Fortitude. Dan Anderssen continues his descent into madness, bringing him face to face with a grief-stricken Michael Lennox.

Dan and Frank go in search of a suspect; however, Dan's feelings for Elena are threatening to overwhelm him. Morton, meanwhile, uncovers a new piece of evidence.

Michael hunts for the place he was held captive, and makes a shocking discovery. Annie Burgess arrives in Fortitude looking for answers.

Following Dan's loss of control, Morton takes over the murder investigation. Elsewhere, Elena's mysterious past is about to catch up with her.

A survivor of the deadly parasite makes a connection with Michael, but things take a violent turn. Dan continues to lose his grip on reality.