Marita doesn't think the police have arrested the right person - but can she trust her own judgement? The researchers face a threat from an unexpected source. Does the accident claim more victims?

As new evidence is revealed, the tensions between the researchers also increase. Shocking information makes Marita question her own principles.

The trains' new control system is praised as reliable, but the evidence does not convince Marita. Marita gets a reason to doubt the impartiality of her own team as well.

Rumors about the cause of the fire inflame the small-town residents. The pressure towards the investigation increases when the track is to be opened to traffic. Marita's carefully guarded secret threatens to come to light.

Eyewitnesses to the accident are vital to investigators - but whose word can you trust? Marita has to make difficult choices when both the relatives of the victims and the government demand an explanation.

The peace of a small town is shattered when a passenger train and a station building are destroyed in a huge explosion and fire. Accident investigator Marita Kaila is facing the most difficult case of her career.