Spoilers for this episode and earlier episodes.
Jonas explores Winden in 1986 and locates Mikkel at the hospital. The Stranger stops him from approaching the boy and explains the consequence of taking him home: Mikkel would never grow into Michael, never meet Hannah, and never father Jonas. Watching young Hannah and Mikkel together makes the choice immediate. Jonas leaves them alone, returns through the caves to 2019, and later burns the letter that revealed his father's identity.
Ulrich pursues Helge as a suspect in 2019 after examining Egon's old investigation. In 1986, Egon questioned Helge about the route he drove when Mads disappeared, but Helge never attended the planned follow-up interview. Ulrich's aggressive visit to elderly Helge ends with a nurse intervening. Charlotte suspends Ulrich from duty. She finally gains access to the power plant and discovers traces of the barrels that have already been removed from the caves.
Katharina confronts Ulrich about Hannah, and Jana gives him another reason to investigate Helge. She remembers a man with a damaged ear arguing with a priest before Mads vanished, then seeing the same man apparently unchanged in 2019. Ulrich finds objects in Helge's room that connect with the investigation and follows him toward the caves. He leaves Charlotte a message suggesting that the answer concerns when the abductions happened. Elsewhere, Helge moves a boy's body and Noah cleans blood from the bunker.