A cargo ship going through Oresund suddenly goes off course and is heading towards the Oresund Bridge. Maritime surveillance calls on the ship but gets no answer. When police investigating the abandoned ship they find five Swedish and Danish youth chained in the hold. This is the beginning of a dramatic crime spree, forcing the Swedish and Danish police to once again cooperate. Saga Norén seeks out her colleague Martin Rohde who is marked by his son's passing. Together they begin the hunt for the unknown perpetrators who are creating panic among the public.

Saga and Martin are quarantined, but when the test results come back negative, they're cleared to leave the hospital, and thus continue their investigation. They're assisted by a Swedish and a Danish officer, Rasmus and Pernille. Someone posts a video online where four individuals wearing animal masks use signs to claim responsibility for the plague. This coincides with several reported passings as a result of eating, among other things, poisoned apples. Saga and Martin are quick to connect the two cases. And they realize this is just the beginning? Martin decides to try to confront Jens a second time. Saga tries to be the perfect girlfriend, but her boyfriend, Jacob, sees right through her.

The militant environmentalists are planning the next attack, larger and more extensive than the previous ones. After an anonymous tip Saga and Martin are close to apprehend them. But when they strike against the groups premises they have vanished. Now the activists know that the police are on their trail. Martin tries to give advice on Saga's personal life, but not entirely successful.

Saga and Martin investigate the hugging of the eco-terrorists. Saga rules out sleeping. They learn there must be a leader still alive out there who's been pulling the strings all along. They track him to a Copenhagen-based IT company, but he seems to have gone underground. Are new attacks being planned? Are there more terrorist cells? Martin hits it off with his Danish colleague Pernille, and the question is whether it's more than just friendship?

Laura , an important witness has memory loss but Saga thinks she may have seen something . The investigation grows and new clues are received. At the same time , carry out a new attack and a movie is put online.

The report picks up when a new case of poisoning linked to Saga and Martin's case. A motor boat salvaged from the ocean floor . The boat finds old bones . What are the inactive persons in the boat ?.

Saga and Martin has a complicated puzzle to put . When a chemical plant threatened to burst it turns out that the attack was data driven and it is the same sender as before. They collect all the clues and will eventually arrive at a common denominator.

Saga and Martin questioning witnesses again and begins to suspect that someone in the group changed the data in the report . Witness Laura wakes up and Martin makes another visit to Jens in prison. Saga tries to find a solution to the problem of cohabitation.

Police now have a phantom image of the offender. Just as Saga and Martin think that the matter is cleared up, it turns out that the great 'end' points towards Heathrow airport. Martin moved back to Mette and Saga and Martin's friendship put to a severe test.

Saga and Martin realise the case isn't over and that there is one more perpetrator. But who is Mikkel Host?.