"Efterforskningen" is a detective mini-series based on real events that took place in distant 2017. At that time, the whole of Denmark was in an uproar due to the mysterious disappearance of a young journalist named Kim Wall. The day before her disappearance, she was preparing to interview inventor Peter Madsen and visit his submarine, the "Nautilus." However, she never returned from the excursion. Shortly after, the police managed to find her dismembered body in the water. The main character of the show is Jens Møller, the head of the Copenhagen police, who is investigating Wall's death.