The lost son and missing brother: October 9th, 1986 was the last time Mads Nielsen was seen in Winden. The town was covered in missing person posters, but the police never found a trace. The boy's disappearance left a lifelong emotional scar in the lives of his mother Jana and brother Ulrich. Everything resurfaces when Ulrich's son – and Mads' nephew – Mikkel Nielsen vanishes in 2019.
The bodies in the forest
On the day after Mikkel's disappearance, police find the body of a boy in the forest, but it isn't any of the current missing children. The boy's eyes are burnt and he's dressed in clothes from the 80s.
Ulrich Nielsen is the only one who uncovers the truth. He recognizes a scar on the boy's chin that matches one his brother got after falling on a glass table in the winter of 1985. But Mads hasn't aged at all and his body isn't decayed. How can that be?
Mads Nielsen was abducted by Noah and Helge Doppler in 1986. They use him to test their prototype time machine in the bunker. The experiment fails and Mads is killed in the process, but his body suddenly appears in 2019. Peter Doppler is in the bunker at the time and immediately alerts Tronte Nielsen. Older Claudia Tiedemann appears out of nowhere and convinces the men to leave the body in the forest.