Back in the classroom, House is kind of annoyed at the Numbers for going through all that grave-robbing trouble and not even noticing that their patient was totally hallucinating. Whatever. I want her illness. I want to hallucinate up my mother when I'm sick and have her sitting by my bed comforting me. Or maybe not, since it turns out that Irene's mother is dead, and has been for the last twenty years. PS says that Irene didn't mention having hallucinations. Well, duh. She doesn't know they aren't real, so why would she report it? The Other Guy reports that all the labs came back fine. Weird Beard proves his worth by saying that while seeing your dead mother is a hallucination, the fact that Irene doesn't realize her mother is dead is a delusion. An old-guy war starts to brew as PS says that carbon monoxide could cause the delusions and Weird Beard counters that Irene has no symptoms of that, and PS's medical school clearly didn't teach him very well. Whereas Weird Beard's medical school is either a hallucination or a delusion.

13 gets back on track by suggesting a family connection. Irene's mother died at the age of twenty-five, which Irene is only one year shy of. Meanwhile, that mother looked pretty damn old for twenty-five. Either life was rough in the Ukraine twenty years ago, or Irene is hallucinating an older version of her mother who never actually existed. That's some sophisticated hallucinating there! Kumar doesn't think they'll have much luck getting the mother's medical records. House agrees. They'll just have to test the patient for every hereditary disease under the sun. In alphabetical order. Let's hope for Irene's sake that she doesn't have ZZTopitis.

The ladies get to deal with the patient, who angrily insists that her mother is not dead and is sitting in the corner of the room right now. CTB persists in upsetting Irene and telling her of her mother's long-ago demise until 13 tells her to leave Irene alone. "Convincing her that her mother's dead isn't going to make her better. Just miserable," 13 says. This gives CTB an opening to ask 13 if she lost her mother. Maybe, or maybe 13 just knows the tiniest thing about human emotions and compassion. You don't have to lose a mom to know that it makes you sad. CTB goes back to torturing Irene, who accuses them of being mean and bad at their jobs. Ghost Mother tells her to be nice, to which Irene says they're doing exactly what "the guy in the wheelchair said they'd do." This gets both of the doctors' attention. 13 asks who Irene's talking about, and she says she's talking about the guy in the wheelchair who's been hanging around the halls complaining about how incompetent everyone at PPTH is. This could literally be anyone PPTH has ever "treated," so Irene narrows it down by adding that 13 also killed the guy's dog. To her credit, 13 remains remarkably composed at this, whereas I totally would have run screaming out of the room. I mean, I don't believe in ghosts, but I might start if I was responsible for someone's recent death.