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.
Northern Quality tells the story of three generations of farmers. Each of them experience different kind of problems, but all of them are linked to some kind of structural change. They seek a solution to their problems by cultivating a more productive crop in their fields: cannabis. This experiment leads to significant problems with international criminals, municipal officials and even the local police officer.