60-year-old police officer Hilkka Mäntymäki, a senior criminal investigator from Oulu, travels to Fuengirola - in Spain - to investigate the disappearance of a Finnish family. At home, she is struggling to cope with her husband, Aarne, who is suffering from dementia, so the opportunity to travel gives her a chance to escape her problems. But following a spate of crimes, she becomes drawn into solving them alongside the Spanish police and soon discovers a connection with Detective Andrés Villanueva.