In 1986, Ulrich is released without charges, and Hannah secretly discovers that a newly arrived young man, who calls himself Aleksander Köhler, is living under a false identity.

Claudia encounters her dog Gretchen, who disappeared in 1953, alive and well by the caves, and starts to read Tannhaus' book. 

When Bernd admits that the hidden barrels contain byproducts of a small meltdown, Claudia hires Aleksander to secretly weld shut the door to them.

In an argument with Helge (revealing that the abducted boys died from Noah's attempt to create a time machine) Noah states his mission to free humanity, likening himself to the Biblical Noah.

In 2019, Hannah uses her knowledge of Aleksander's past to blackmail him into destroying Ulrich's life. She lies to Katharina that Ulrich wanted to leave his family.

Regina discovers the Stranger's research and start thinking by seeing the know face on the wall, whereas Jonas breaks things off with Martha.

Bartosz is approached by an elderly Claudia, his supposedly dead grandmother. Later, Bartosz meets with Noah and agrees to join him.

In 1953, Helge has been reported missing, and Noah – appearing the same age as in 1986 and 2019 – offers pastoral support to Helge's mother, Greta.

Egon tries to catch Ulrich and finally he is arrested and confesses to murdering Helge.  Egon take Ulrich to the prison.

The Claudia of 2019 enters Tannhaus' shop with blueprints for the brass machine, asking him to build it for her.