Martha meets the Stranger and learns his true identity. Claudia tries to prevent Egon’s death in 1987. Hannah travels to 1954 to see Ulrich.

Armed with a plan to prevent the apocalypse, Jonas travels to 2019. During the Nielsens’ anniversary party, Ulrich sneaks off with Hannah.

In 1987, Ulrich seizes an opportunity. The kids return to the cave with the time machine, and Jonas learns of a loophole that could change the future.

Clausen and Charlotte interview Regina. The Stranger takes Hannah to 1987, where Claudia has an unnerving encounter and Egon visits an old nemesis.

Peter gets a shock. Jonas learns the truth about his family, but there are more surprises still to come. Helge makes a sacrifice.

Ulrich runs afoul of the law, Helge tries to dodge Egon Tiedemann, Claudia harnesses the cave’s powers, and Katharina lashes out at Hannah.

Ulrich questions a frail and frightened Helge in the nursing home. Jonas searches for Mikkel, but the stranger warns him about meddling with the past.

Hannah takes her obsession with Ulrich too far. The stranger asks Regina to deliver an important package. Martha is torn between Jonas and Bartosz.

It’s 1986, and Ulrich’s brother, Mads, has been missing for a month. Confusion reigns as past and present intertwine.

When a grim discovery leaves the police baffled, Ulrich seeks a search warrant for the power plant. A mysterious stranger checks into the hotel.

In 2019, a local boy’s disappearance stokes fear in the residents of Winden, a small German town with a strange and tragic history.

Adam holds Martha captive in 2020. On the day of the apocalypse, an increasingly frantic Martha begs Bartosz for his help.

In 2020, a visitor delivers a warning to Claudia. The day before the apocalypse, Jonas begins to question Eva’s motives.