A Spanish-Finnish couple is found murdered in cold blood in the Oulu region. Hilkka Mäntymäki and the "new sheriff in town" Jami Kalliola start investigating the case.

Hilkka Mäntymäki's team is strengthened by the arrival of Luisa Salinas, flown in from Spain. The investigation leads the police on the trail of a transport company specialising in the waste business.