Mari, an Intelligence Agency officer goes undercover to befriend an asylum seeker who has arrived in Finland. Why? Because the refugee in question is Madina Taburova, one of the most wanted terrorists in the world, now presumed dead. Mari sets out to win Madina's trust in a mission to uncover what her intentions are in Helsinki.

Mari gets Zamira to the hospital, where she falls into a critical condition. The doctor tells Mari that there were drug packets in Zamira's stomach and one of them had leaked. Viita has followed the ambulance to the hospital and is surprised to find an armed guard at the door to Zamira's hospital room. Mari goes back to the refugee center and finds the passport Zamira has hidden in her room. The passport is a forgery - and a very good one.

Madina/Zamira is escaping the hospital with a gun and a phone stolen from the guard whom she knocked unconscious. Mari arrives at the hospital to find out Zamira has escaped. Viita also arrives at the hospital and sees Juri, who strikes him as suspicious. When Viita decides to follow Juri, the man disappears. Madina steals a car and drives away, guided by the phone's satellite navigation application. Mari knows where Madina is heading.

Viita interrogates Madina, who is still posing as Zamira Hoxha, the drug mule, when Mari tells him the truth. Mari and Karla Tuomi want Viita to work with the Security Intelligence Service in order to find out what the terrorist Madina Taburova is planning to do in Finland. Viita agrees to this, even though it means keeping secrets from his own superiors and letting Taburova walk free, so the police can track down the whole terrorist cell.

Mari and Viita are perplexed by the security equipment malfunction and the photographs that have appeared in Madina's possession. Was she is visited by the same man, the Ghost , whom Viita saw at the hospital and Mari's apartment building? Mari sneaks into Madina's place and is almost caught while copying the photos of the teenage girl. Viita and Mari wonder about the identity of the teenage girl, the one in the photos found in Madina's place. Mari meets with Madina in her guise as a social worker, trying to pry some answers, but Madina doesn't give anything away.

Karla Tuomi is furious, as Mari has met Alba without her permission or order. When Madina returns home, Juri is waiting for her in the apartment building hallway. He instructs Madina to attend a job interview. Juri also gives her two Qurans and a vial of poison. He orders Madina to kill the nosy social worker. Vili and Jaska follows Madina to a five-star hotel. It turns out that she has secured a cleaning job there.

Madina has to explain to Juri why she didn't poison Mari. Karla Tuomi gives Mari a direct order - she is to stay away from Alba and keep the focus of the investigation on Roza and Zara. Madina offers Roza and Zara help to get cleaning jobs at the same hotel she works in. Zara and Roza are immediately interested. Viita convinces Karla Tuomi that it is a good idea for Madina and Alba to meet. With Tuomi's blessing, Mari meets Alba and tells the girl that her mother is alive and in Helsinki.

Mari and Madina return to Madina's place, where badly beaten Zara is waiting for them. The women drive to Zara's apartment, where Madina finds a badly bleeding Konstantin. Zara has stabbed him with a letter knife. As Zara waits in the car with Mari, Madina finishes what Zara started by choking Konstantin to death. Mari and Madina dump the body into the icy waters of the harbour.

Juri kidnaps Madina and brings her to an empty house which he and his mercenaries use as their headquarters. Mari has killed her attacker. She and Viita wonder about the man's identity at the morgue. Tattoos hint at a background in the Russian military. Roza's mother finds the Quran in her daughter's room and becomes worried. For the first time in ages, the two have a good long talk. They decide that Roza will quit the job at the hotel and concentrate on her studies.

Mari wakes up in an empty garage. The bullet had just grazed her. There is a barrel filled with explosives. In a van heading for Helsinki city center, Juri presses the button to detonate the bomb, but Mari manages to disarm it in time. Meanwhile Tuomi tells her team the president of Russia is having a secret meeting in Helsinki, taking the Security Intelligence Service completely by surprise.