A missing child sets four families on a frantic hunt for answers as they unearth a mind-bending mystery that spans three generations.

1. Secrets 52m In 2019, a local boy's disappearance stokes fear in the residents of Winden, a small German town with a strange and tragic history.

2. Lies 45m When a grim discovery leaves the police baffled, Ulrich seeks a search warrant for the power plant. A mysterious stranger checks into the hotel.

3. Past and Present 46m It's 1986, and Ulrich's brother, Mads, has been missing for a month. Confusion reigns as past and present intertwine.

4. Double Lives 48m Bizarre occurrences give Charlotte a sense of déjà vu, and she suspects Peter is hiding something. Franziska snaps when Magnus confronts her.

5. Truths 46m Hannah takes her obsession with Ulrich too far. The stranger asks Regina to deliver an important package. Martha is torn between Jonas and Bartosz.

6. Sic Mundus Creatus Est 51m Ulrich looks to the past for answers and dredges up disturbing family secrets. Armed with new tools, Jonas probes the cave's murky depths.

7. Crossroads 52m 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.

8. As You Sow, so You Shall Reap 50m In 1953, the disfigured bodies of two boys are exhumed at a construction site, the future location of Winden's nuclear power plant.

9. Everything Is Now 55m Ulrich runs afoul of the law, Helge tries to dodge Egon Tiedemann, Claudia harnesses the cave's powers, and Katharina lashes out at Hannah.