Anton Mehringer is attacked in a dark alley by an unidentifiable person and is critically injured until a plainclothes policewoman intervenes and puts an end to it. Mehringer suffers from a coma and is transferred from the emergency ward to a clinic where they deal exclusively with coma patients. Sarah Kohr is deeply shaken that her only confidant may never come out of the coma again. She promises Mehringer's ex-wife Anna that she will do everything she can to find out the background of this attack.
In addition to the police officer July Bastrich, who apparently prevented worse by her intervention, Sarah Kohr also investigates other suspects, whose tracks all lead to Prof. Dr. Gabriele Keuber's coma ward. Apparently, Anton Mehringer had received tips in this direction before he was attacked and is now to remain silent forever...