Ben was talking to Megan just before the explosion and was a witness to the building collapse. He assisted the emergency personnel, who thought they had found Megan in the rubble. Unfortunately, both Ben and Mrs. Bradberry had misidentified Liz Masters, who was the same build and general description, at the accident site. Subsequently, Megan was found, but was misidentified as Liz.
Surgery for the patient went well, but "Megan" had a fever that would not abate. Lisa Cuddy convinced Gregory House to take the case, even though he had no team. Dr. House was convinced he could solve the case himself and approached Ben and Megan for a medical history.
After an environmental scan, Dr. House came to the conclusion that the patient was suffering from clinical depression and had been taking antidepressants, which had interacted with the demerol. Ben insisted that Megan was not taking antidepressants, but Dr. House had a diary showing Megan was having difficulty in her relationship with Ben. Mrs. Bradberry agreed to treatment.
"Megan" improved, but developed tachycardia. After reviewing the case again, Dr. House came to the belief that the patient was suffering from delerium tremens. However, once again, Ben objected, saying there was no way Megan could be an alcoholic without his knowledge. Mrs. Bradberry agreed to give "Megan" intravenous alcohol,
Once again "Megan" improved, However, she is soon in intense pain and starts bleeding. Dr. House schedules surgery to stop it, and during surgery finds that "Megan" has had a recent abortion and that her bleeding is a result of her being on the pill. When he breaks the news, Ben is once again incredulous - he tells Dr. House that she is trying to get pregnant. However, Ben agrees to the course of treatment House wants.
However, "Megan" then has an adverse reaction to the blood thinners. Dr. House is stumped, but finally learns that she is having an allergic reaction to one of the antibiotics she has been given. However, Ben is aware that Megan was on the same antibiotic a few months ago, and had no adverse reaction. At this point, even Mrs. Bradberry has lost faith in Dr. House.
However, Dr. House finally realizes the problem. He reviews all the medical records of all the trauma victims from the gas explosion and reviews Liz Masters' file. She is on antidepressants, is allergic to antibiotics, is a heavy drinker, and has had a recent abortion. He confirms the patient is Liz and everyone realizes that Megan died several hours ago, as they thought Liz had died. Dr. House consoles Ben by telling him his girlfriend never did lie to him.
Later, Dr. Cuddy admonishes House for not believing Ben. She reminds him that if Allison Cameron had been on the team, she would have trusted Ben and come up with the right answer sooner.