At the age of 44, artist Michael Kahnwald commits suicide in the attic of his home for no apparent reason. He is survived by his wife Hannah, son Jonas, and adoptive mother Ines Kahnwald. Ines secretly takes the goodbye letter Michael left even though it was addressed to Jonas.
Michael Kahnwald and Mikkel Nielsen are one and the same person. When Mikkel disappears in November 2019, he travels through time and lands in 1986. The distressed boy, assumed to be homeless, ends up in the hospital. Nurse Ines Kahnwald cares for him there and eventually adopts him as her son, calling him Michael.
Michael can't find his way back to 2019, so he remains in the past and starts a new life. He spends years studying the caves where he first found the passage and makes a detailed map. Following Michael's suicide, Jonas finds the map amongst his father's things in the attic.