Spoilers for this episode and earlier episodes.
In 2019, the search for Mikkel continues while Charlotte examines the unidentified boy found in the woods. His burned eyes and damaged ears do not explain why he carries a Walkman and wears clothing associated with the 1980s. A coin dated 1986 hangs around his neck. Ulrich enters the caves and finds a locked metal door leading toward the nuclear power plant, giving him somewhere specific to focus his desperate search.
Aleksander blocks police access to the plant and orders Jürgen Obendorf to arrange the removal of concealed material. Ulrich follows a separate suspicion to Jürgen's property, where he discovers the drugs Jürgen and Erik were selling together. That discovery supplies no answer about Mikkel. At home, Tronte secretly washes blood from his clothing and gives Jana an unconvincing account of his movements during the previous night.
A stranger checks into Regina's hotel carrying a suitcase with a mechanical device. In Michael's studio, Jonas finds a detailed map of the caves hidden above the ceiling. These discoveries unfold while the Nielsen family waits for news and Ulrich turns away Hannah's attempts to resume their affair. Mikkel finally emerges from the cave and runs home, but his key no longer fits. He meets teenage versions of Ulrich and Katharina, then sees a newspaper establishing that he has arrived in 1986.