A detective is forced to confront difficult home truths about his past, and his present, while on the trail of a serial killer in rural northern Finland.

A huge train accident in an idyllic small town shocks the whole of Finland, and accident investigator Marita Kaila is faced with the most difficult case of her career. Under increasing pressure, Marita and her team try to find out what led to the death of dozens of people. But there is also a tragedy in Marita's own past, which the demanding investigation brings to the fore. Will he solve the case before the pressure becomes too much?

The life of the Kurtti family changes completely on one fateful, midsummer night. Years later, secrets start to unravel and show how far each of them are willing to go for their loved ones.