Arctic Circle (aka Ivalo) is set in the unforgiving polar region, amidst the icy landscapes of Finnish Lapland. In season 1 Nina Kautsalo, a Finnish police officer, finds a dying prostitute in an old cabin in the wilderness, the ensuing criminal investigation takes a surprise twist when a deadly virus is discovered in her blood. Nina suddenly finds herself in the middle of an exceedingly unusual criminal investigation. In season 2 Nina joins a new police unit in order to solve the mystery of an international hunting society. It's tied to an old murder case, to which Nina has a surprising connection.
Nina settles 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.
Nina returns to Ivalo-and to a new partner, Viktor. 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 to follow their investigation to a remote location-with potentially deadly consequences. Meanwhile, Marita and Esko grow closer as they worry about Venla.
Viktor opens up to Nina about his past. Nina files a report 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 someone 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.