Spoilers for this episode and earlier episodes.
The finale returns to Mikkel's disappearance in 2019 and reveals what Peter and Tronte concealed. Mads's body appears through a rift inside the bunker; Peter calls Tronte, and an elderly Claudia instructs them to move it into the woods. Later, Jonas confronts Ines about Mikkel and receives the original letter she kept. In 1986, Ines asks to foster and eventually adopt the boy rather than allow him to enter a children's home.
Jonas returns to 1986 intending to bring Mikkel back, but Helge captures him at the hospital. Locked inside the bunker, he meets the Stranger through its door. The man reveals that he is Jonas thirty-three years older and refuses to release his younger self, saying these events must happen for him to become who he is. Elsewhere in 1986, elderly Helge tries to stop his younger self. His deliberate car crash kills the older Helge while the middle-aged version survives.
The Stranger activates the repaired machine in the cave passage, hoping to close the wormhole. Noah tells Bartosz that this attempt will instead help create the wormhole, despite the Stranger's hopes. A rift connects Jonas in the 1986 bunker with young Helge in 1953. When they touch, Helge is transported to 1986 and Jonas awakens in a devastated future Winden. Armed people surround Jonas, and a woman welcomes him to the future before knocking him unconscious.