Aleksander Tiedemann is director of the nuclear power plant, making him one of the most powerful men in Winden. He seems serious and confident, but he has secrets to hide. He is caring towards his wife Regina, especially after finding out she has cancer. Together they have a son, Bartosz.
Arrival in Winden
In November 1986, a young man with a gunshot wound is running through the forest near Winden when he witnesses Katharina and Ulrich Nielsen threatening Regina Tiedemann. The man pulls out a gun and drives away the attackers. Regina is grateful and tends to his wound. They soon become a couple.
The young man is hoping to start a new life in Winden. He has two passports: one with the name Aleksander Köhler and the other with Boris Niewald. He buries the latter with the gun in the forest, but Hannah Kahnwald sees him and takes the bag with the compromising materials.
She waits until 2019 and then blackmails him. She demands the man, who is now called Aleksander Tiedemann, use his power in Winden to destroy Ulrich Nielsen's life.
Aleksander and the yellow barrels
When Aleksander arrives in Winden, he goes straight to the nuclear power plant and asks for a job. He introduces himself to director Claudia Tiedemann as a friend of her daughter's. She hires him to carry out a confidential job: He must seal off the cave beneath the power plant where yellow barrels of atomic waste are stored.
Thirty-three years later, Aleksander is director of the plant and he's determined to keep the existence of the yellow barrels a secret – even from the investigations of Ulrich Nielsen and Charlotte Doppler. Aleksander is kept up-to-date on the police investigations by his contact man Wöller. When the police threaten to search the power plant site, he has the yellow barrels loaded onto a truck and left at a truck stop.