The authorities expect the case of Friedel Walter, alias "Dr. Mueller," to be a straightforward one: he was working as a doctor without proper credentials under a false name. But Mehlin, the man in charge of his case, knows that there is more to the story. When he was injured fleeing from a concentration camp, resistance worker Irene asked her medical student boyfriend Walter to give him medical care.
As it turns out, Walter ended up on the front as a medical worker, was taken captured by the British and mistakenly registered under the name of the fallen Dr. Mueller. He simply never straightened out the confusion. Years later, while dealing with a particularly difficult case, he recognized the patient's wife as his former love Irene and was forced to confront the truth about his past.