Julia searches for the two engineers who had saved the nuclear plant from another meltdown by exposing themselves to lethal doses of radioactivity.

The true story of the radioactive leak at the nuclear plan that triggered the killings is revealed.

Héctor and Julia continue to close in on the answer to the question of why the decontamination company has been hunting down five of its workers who fled from their corporate apartments just before the first killing.

While solving the murders, Héctor, Martín and Zoe form a pact to keep important information secret. Héctor continues to uncover the conspiracy behind the decontamination of the zone.

As it becomes more obvious that the company in charge of decontaminating the zone, AFRAXA, is engaged in dirty-dealings, Héctor and Alfredo are sure it's a key to the case.

Guilt-ridden by the mistakes made at the meltdown three years ago, Julia single-handedly and without back-up from her superiors closes down a school when contamination levels suddenly surge.

Héctor and his partner Martín aren't thrilled when a federal agent is assigned to their case. Is he there to cover up what they increasingly think the local government is trying to hide, or to help solve the killings?

Three years ago a nuclear power plant in Spain suffered a meltdown causing hundreds of fatalities and the creation of an exclusion zone. On the anniversary of the accident, a man is found murdered and cannibalised.