After her unconventional methods get her fired, Rebecka sinks into another deep depression. But a shocking revelation about one of the mining owners puts her back on the case.

Mella leads an investigation into the drowning of a young diver trapped under ice for a whole winter. But the water in her lungs doesn’t match the river in which she was found.

The discovery of another body and the unearthing of an old Nazi airplane near the mountain lake provide Mella and Rebecka more clues to the truth. Rebecka has misgivings about her life with Måns as she grows closer to police dog handler Krister.

Rebecka plans her move back to Stockholm but reconsiders when she and Krister discover the body of a woman brutally murdered. The only witness is the victim’s young grandson, now alone and too traumatized to speak.

Despite resigning, Rebecka continues investigating the case, focusing on the victim’s father, who was eaten by a bear. Meanwhile, Mella and her team discover the murder weapon in the barn of one of the victim’s lovers.

Construction workers uncover human remains under the floorboards while demolishing an old building. The police identify the body as a young mother named Linn, who disappeared sixteen years ago. Elsewhere, Rebecka learns an old family secret when a friend suffers a heart attack.

Linn’s husband remains the prime suspect, but there’s not enough evidence to charge him. Mella’s team follows up on the origin of the plastic sheeting covering Linn’s body, but they still have not found the murder weapon.

When a young man overdoses while sampling a new drug batch at a party, the police attempt to track down the dealers, but Mella doesn’t realize her own daughter is involved. Rebecka plans a trip to Stockholm while hiding her condition from Krister.

Mella worries for her daughter’s safety when an informant turns up dead after asking to speak with Mella. Following a public breakdown in Stockholm, Rebecka returns to Kiruna with important decisions to make about her future.

Mella is convinced they have the killer, but Rebecka believes the suspect’s confession is false. After complaints that Rebecka won’t let it go, Rebecka’s boss forces her to go back on sick leave.

After a heavy snowstorm, a plow driver finds a car buried in the snow with a dead woman inside. The victim had a head injury inconsistent with a crash, and her newborn baby in the back seat froze to death. Still recovering from her accident, Rebecka returns early from medical leave to help with the case.