In the middle of the summer holidays, the body of a drowned man with ligature marks on his wrists is recovered from Tammerkoski river. The investigation by Koskinen's team is further strained by the hit-and-run case of a dubious music manager and the mysterious Carl Friedrich. When a new body is found in Lake Näsijärvi, the connection between the victims is made clear.
The series follows Inspector Sakari Koskinen and his team in the Violent Crimes Unit as they try to solve murders in a Finnish lakeside city of Tampere.