Calder and Tosh must work together to find the armed killers and prevent further disaster. Howell and Nowak take refuge with a local and wait for a means of escape.
Tosh believes she has the murderer in custody and tasks the team with finding the evidence to charge. Calder suffers in silence with Jean’s revelation.
Calder initially reels from the awful news, but quickly becomes suspicious. Tosh worries Harry and Donnie with her pursuit of a controversial new theory.
As the investigation draws to a close, Tosh and Calder try to unravel the mystery at the heart of the Bains. The identity of the killer lies in the reason why Ellen left Shetland.