Nina and her daughter settle into life in a new city. After first rejecting an offer to work on an assassination case, a dramatic turn linking the murder to Nina's former case forces her to reconsider. Originally aired in Finland as Ivalo.

Nina returns to Ivalo-and to new partner, Viktor-and leaves Venla in Marita and Esko's care. Their investigation takes the pair to St. Petersburg, where a dangerous encounter with a high-ranking official provides an alarming discovery.

Using stolen evidence, Nina convinces Viktor they should follow their investigation to a remote location-leading to potentially deadly consequences. Meanwhile, Marita and Esko grow closer as they begin to worry about Venla.

After narrowly escaping, Viktor opens up to Nina about his past. Nina files a report about their capture and is dismissed from the task force. Determined to solve the case, Nina learns she must confront someone from her past for answers.

Nina meets an important figure from her past, and is quickly faced with the potential of his involvement in her case. Meanwhile, Nina's family faces a tragedy as she begins to grow suspicious of Marita and Esko's relationship.

With the truth finally revealed, Nina rushes to stop the hunt and save a life-but will she make it out alive? At her grandmother's grave, Venla shows a wisdom beyond her years.