Billy came home one day and found a very upset Margaret, who was worried that there was someone in their house. However, she soon started vomitting and Billy rushed her to the hospital.
As the doctors tried to diagnose her, they started looking into her medical history and found out what she told the doctors didn't match the records. The new hire, Dr. Kelly Benedict, also discovered "Margaret" was using someone else's social security number. When she was confronted about it, Margaret told Billy she had been in an abusive relationship and had changed her identity to escape him. Billy wanted to know who the man was, but Margaret refused to tell him.
However, Billy found a man by the same name in Margaret's address book and went to confront him. However, he got beat up and it was clear the man he confronted didn't know what he was talking about. Dr. Benedict tried to reassure him that abuse victims commonly act this way and he shouldn't confront her about it.
However, House eventually realized that Margaret was hiding the symptoms of schizophrenia and started treating her with anti-psychotics. She was soon lucid and had to admit to Billy that she was lying to try to hide her condition.
Billy asked Dr. House what he should do. He didn't feel he was capable of dealing with Margaret's illness and she didn't seem to be the woman he married. Dr. House got angry and said that relationships meant you didn't bail on people just because they were sick, and Margaret had always been schizophrenic and needed his support. Billy finally returned to his wife's side.