Contains spoilers for this episode and earlier episodes.
Claudia tells Adam that the true origin lies outside both his world and Eva's. In a third world, Tannhaus tried to recover the family he lost in a car accident, but his experiment created the two tangled realities. Destroying Martha's unborn son could never remove that cause. Claudia has identified the brief interruption of cause and effect during the apocalypse, and tells Adam to use it to send Jonas and Martha to prevent the accident instead.
Adam reaches Jonas before the original apocalypse and gives him the travelling sphere. Jonas then takes alternate Martha before Magnus and Franziska can recruit her. Together they enter the cave passage on the day Tannhaus's experiment creates their worlds. A corridor of light lets each glimpse the other as a child before they cross into the origin world. There, they stop Marek Tannhaus's car and warn him away from the bridge. Marek returns home with Sonja and their baby Charlotte, removing the loss that drove his father to build the machine.
Adam visits Eva with an unloaded gun and tells her that he has chosen another path. As Marek's family reunites, Jonas and Martha hold hands and disappear, followed by the people bound to the knot in their two worlds. In the surviving origin world, Regina shares dinner with Hannah, Katharina, Peter, Bernadette and Wöller. A power cut prompts Hannah to describe a dream of darkness and release. Asked about her unborn child's name, she says that she has always liked Jonas.