Officer Sandy's grandmother Mima is gunned down on the island of Bresee in Shetland. Ironically, Sandy was the first one to find her. The human remains were found on Mima's land, which had been the site of an archaeological dig. The case becomes more mysterious when Hattie James, a student working there, is found dead.

[Season Finale] Hattie was wearing a necklace given to her by Mima, the same one worn by the Norwegian, Per, in a wartime photograph. Mima's husband, Jerry, was transporting agents, supplies, and money to Norway at the time, under the radar of the Germans. Pär disappeared along with a large sum of money. He had to eliminate whatever threats to his family.

On the evening of the summer solstice, Catherine and Sally were attending a party on the beach. On their way home, they stop by the house of Magnus, a recluse. Catherine was a heretic and shunned by the adults. Two days later, Catherine's body is found on the beach.

The body of Catriona, who had been missing for 19 years, was found holding a doll of Magnus' sister Agnes, who had died when she was 6. Inspector Perez brought Magnus to the station for questioning, but she would not talk. Sandy argues that since Catriona and Catherine's murderer have nothing in common, it is unlikely that Magnus killed them.

Captain Perez's old friend, reporter Jerry Markham, returned home, but the next day Markham was killed in an accident in which he was rear-ended by someone. Markham's broken computer had recorded a video opposing the gas company's new pipeline. Inspector Perez investigates Dalhousie, the landowner of the fish farm where the pipeline will run.

Officers Perez and Sandy visit Dalhousie and see a house with harassing graffiti saying "Get out. John, who was going to marry Evie, who runs the "Cove Preservation Society," was attacked by someone and left for dead. The paint at the two crime scenes, Jerry's and John's, and the paint on the Dalhousie house graffiti turned out to be identical.