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. ...

Jonas meets an ominous figure. While the kids comb the cave for answers, the adults gather in the bunker to share what they know about the travelers. ...

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 looks to the past for answers and dredges up disturbing family secrets. Armed with new tools, Jonas probes the cave's murky depths. ...

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

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

The small german town of Winden is shook by the disappearance of a teenage boy. Some of the townsfolk look back to the events thirtythree years ago, when another teenage ...