Carl Morck and the Q Department are back with their ninth case.

Homicide chief Marcus Jacobsen meets with his best investigator, Carl Morck, about an old case that touches him personally. The members of Department Q begin to grow an unpleasant tangle of long-closed cases under their hands. A challenging task forces Carl, Asad, Rose and Gordon to bond tighter than ever.

After investigating the deaths of high-profile figures that the police had previously dismissed as suicides or accidents, Q Department uncovers a grisly pattern to the perpetrator's behavior. All indications are that the murders are not over yet. In order to prevent another cruel death, they embark on a fierce battle for time in the difficult time of anti-covid measures. But in the meantime, a completely different case emerges from Carl's past like a snake about to attack its prey.