While Head of Homicide for Copenhagen Police Jens Møller comes in for the morning briefing, an investigator reports on a strange case. A homemade submarine carrying a female Swedish journalist and the submarine's inventor has gone missing.

Jens Møller is constantly under pressure from journalists who are chasing news of the case. Meanwhile, rumours and theories abound. Were the Swedish journalist and the accused previously acquainted?

While the forensic team works, Jens Møller and his team of investigators are waiting for answers. Have they found conclusive evidence that the Swedish journalist is dead, and if so, has a crime been committed?

Jens Møller gets assistance with the search. Swedish cadaver dogs that can locate bodies more than 20 metres below sea level are brought in. Although the dogs mark the areas quite accurately, the divers don't find anything.

The case is slowly coming together, but Jens Møller and his team still have no conclusive evidence. Chief Prosecutor Jakob Buch-Jepsen emphasises that they must determine the motive and cause of death in order to charge the accused.

Chief Prosecutor Jakob-Buch Jepsen makes it clear to Jens Møller that they need more firm evidence to bring charges in the case. Otherwise, they risk the accused walking free.