The Cottages wait for House to show up. Chase randomly sniffs his pencil and says he knows exactly why their boss is late, since he saw him leaving with Stacy. Naïve Young Cameron says that House was probably just walking Stacy to her car, because we all know how easy and painless walking is for House so I'm sure he'd do some extra as a favor. She says that House isn't an "idiot" who would sleep with a married woman. It would just kill her to find out that he was, though, since we all know how Cameron feels about people who cheat, especially in a marriage, and she'd have to make an exception for House since she likes him so much. Foreman, as usual, looks at how the situation benefits him and says he hopes that House did get laid because maybe then he'll be nicer.
House finally shows up, singing away and generally looking like someone who just had sex. Another reason for his happiness is that he won his bet with Foreman -- Cameron didn't take her test. Cameron shrugs it off, saying that she already had a viral load test that's 99.9% accurate. Chase seems particularly concerned about the situation, probably more for his own drug-sex-having sake than for Cameron's. She changes the subject back to their patient, whose health problems can no longer be blamed on the Ritalin. But no condition explains all her symptoms. House suggests that SuperMom's fertility drugs caused some endometrial cancer, which explains the clot that caused her stroke. The Ritalin explains everything else. He tells the Cottages to do an ultrasound on SuperMom's uterus and look for something growing in there that "doesn't look adorable in a onesie." Since were tumors not cute? Come on now! Some of them even come with hair that you can comb and style. House stops Cameron on her way out and sincerely declares his love for her. When she does her imitation of StuporDad and drops her jaw, House sticks a Q-tip in her mouth and swabs. She'll get her HIV test results back tomorrow, he says. Cameron doesn't really know what to say or do about what just happened, so she just turns and walks out. Aw, see, now, there was one of House's redeeming moments. It doesn't make up for his comment about Chase's dead dad, though.
House is studying what appears to be the sunrise on the roof of ridiculous sky backdrops when Stacy finds him. He smiles when he sees her. Aw. She's holding a prescription for a heart condition, which is House's idea of a romantic present. Stacy calls it "cheesy," because she sucks. They hug, and House ruins the moment by asking her if she told Mark about them. Guess what? She didn't. And she doesn't know how to do it without hurting him. That's because it's impossible, Stacy. And where was all this concern for Mark's feelings BEFORE you threw yourself at House? She has a great solution to the whole mess: "if I don't tell [Mark], it'll never hurt." Now it's House's turn to do a StuporDad as he realizes exactly what Stacy is saying to him. I guess it's wrong to hurt Mark, but totally awesome to hurt House, right, Stacy? As long as you get everything you want, it doesn't matter how anyone else feels. She says that she still loves Mark, and the situation that she put herself in is not as simple as House would like it to be. House takes a breath and tells her that she can either be with him or with Mark, but not both. "It's not easy, but it is simple," he says. Sela Ward tries to make some sort of facial expression, but she can't, so she has to settle for expressive swallowing and teary eyes. If not for that, though, you'd swear she was bored.