Hanna is a 30 something single woman from Helsinki. She has a good job and great friends and has almost given up on finding the Mr. Right. One night, Hanna meets Markus, a dark stranger who sweeps her off her feet.

The series tells the story of DI Kari Sorjonen of the Serious Crime Unit in Lappeenranta, his family, and his investigations into a variety of harrowing homicides around the border area.

Imaginaerum tells the story of an elderly composer, Tom, who suffers from severe dementia. As he has had the disease for years and has regressed into childhood, he remembers practically nothing from his adult life. His music, friends, all his past including the memory of his daughter are a blur in his fragile mind. All he has left is the imagination of a ten year old boy. As he drifts away into coma, it seems impossible to get back what he has lost. Or is it?