Niki receives a letter from a woman, Elvira Strasser, who says she was convicted for a crime she didn't commit. Not long afterwards, Niki discovers that the woman has apparently committed suicide even though she only has six months left of her sentence. Against Marc and Kunz's wishes, Niki goes undercover in the prison to find the truth, but finds herself in danger.

Katja and Matthais, best friends, are at a building site taking photographs. A body is later discovered at the site and Marc meets an elderly woman who lives in the unfinished building.