It follows Jimmy Perez and his team as they investigate crime within a tight-knit island community in an isolated environment, as the team must rely on a unique style of law enforcement.
The case of 17-year-old Catherine Ross prompts Detective Inspector Jimmy Perez to reopen the investigation into the disappearance of a teenage girl years ago, while the personal secrets of the two teenage girls before their passing reveal the answers to the mystery.
A young man disappears in Shetland, prompting Detective Perez to investigate his past, before the case becomes more complicated with the belief that the missing person is a criminal on the run.
Detective Ruth Calder teams up with Alison to find a witness to a case before it's too late. Then, they race against time to prevent a major disaster at the hands of serial killers. At the same time, a sudden investigation takes a mysterious turn when a strange tattoo appears.
The terrifying tales of disappearances begin to unfold in the ninth season, as Tosh and Calder embark on complex investigations that challenge the line between personal and professional life.