Spoilers for this episode and earlier episodes.
Ulrich follows elderly Helge through the caves but emerges in 1953. Police have discovered two boys' bodies at the site where the nuclear power plant will be built. Their injuries resemble those of the boy found in 2019, while their possessions include coins dated decades ahead. Ulrich encounters Agnes Nielsen and her son Tronte, then visits the police station. Egon confirms that neither dead boy matches Ulrich's description of Mikkel.
In 1986, the Stranger discusses time travel with clockmaker H. G. Tannhaus. Their conversation describes a passage linking three periods separated by thirty-three years, rather than a simple journey between two dates. The Stranger wants to know whether events can be changed. He eventually presents his damaged machine and asks Tannhaus to repair it. Tannhaus recognizes a connection between the device and his own work, while the Stranger explains that he has already traveled through time.
In 1953, Ulrich realizes that Helge is still a child. At first he encourages the boy to stand up to bullies, but later decides that killing him could prevent the future abductions. Helge runs from Ulrich, who catches him and strikes his head repeatedly with a rock. Ulrich carries the unconscious child into the bunker and locks him inside. Mikkel is still absent when Ulrich leaves, convinced that attacking Helge will prevent the abductions and spare the children in the future.