House's office, where the good doctor has added "cardiac arrest" to the big board, and Foreman is in the middle of arguing, "We've got lung and kidney failure, neurological symptoms, and now cardiac arrest. A systemic disease with multi-organ involvement is the definition of lupus." It's not...eh, nobody listens. House does, suggesting that they start Bob on interferon, which, while not a treatment for lupus OR heavy metals, is the best method of treating -- dun DUN duuuuuuun -- a viral infection. Brows crease across America.
Mrs. Bob reacts badly to this. She thought it wasn't a viral infection. In fact, she thought it was lupus, on account of her doctors telling her that. Foreman tells her that the rapid progression of the symptoms have caused them (well, House) to reevaluate. She asks what happens if they're wrong again, and Foreman tells her that, with Bob's lungs, heart, and kidneys all failing, they don't have much of a choice. "Lungs, heart, and kidneys"? He can use the big words. We know she knows them.
Later. Mrs. Bob sits on the edge of her husband's bed, acting all sad and non-murder-y. He wakes up briefly, sees her there, clears his throat, and lowers the boom: "I cheated." Ah-HA!!! What a dramatic fourth-act admission, sure to prove the dastardly method by which his wife-- "Ninth-grade Earth Science." I...oh. "Mr. Foley." Dude, I cheated in that class, too. That guy was a dick. "I sat behind you so I could cheat off of you." Mrs. Bob pillow-talks that she let him cheat so that he would sit behind her. Awwwww, Earth Science gifts of the Magi! Bob says that he thought they would grow old together, but instead she's trying to kill him. Well, he says some of that. He says he loves her and she refuses to say it back, claiming, "Because you're not dying." He begs her to say it anyway, threatening, "You gonna make me hurt you?" Like her heavy metal vagina isn't doing all of the hurting in this relationship.
Foreman reports to House that the interferon isn't working, and House insists that they keep upping the dose. Just then, House's beeper dings...
...and we cut to House entering Cuddy's office, late for his meeting with the Lamberts. Mr. and Mrs. Herpes sit next to each other, each looking mighty peeved. House gets right to work: "Your wife has herpes." She claims that this is impossible, but he tells her that she hasn't had an outbreak yet, but that she will, real, real soon. Mrs. Lambert calls her husband a "ruddy jackass," which, unless "ruddy" is fake-Anglo for "not a," cannot be construed as a compliment. Mr. Lambert once again promises that he hasn't been with anyone else in twenty years, and when she tries to claim that he's the one with the sores on his suzie, House corrects her that that doesn't mean he got it first. Mrs. Lambert says that there has to be some way to prove who brought home the early Christmas present, and when Cuddy says there's no test, House busts in, "Either of you two ever sit on a public toilet?" Cuddy looks at him like he's gone bonkers, but House explains that herpes can live outside the body for very short periods of time. The proper lady says that she always uses a paper cover, but her dirty, dirty husband takes this opportunity to admit that he doesn't always. And that's why he has herpes! Except, yeah. Take it, House; "He could believe you can get herpes from a toilet seat, or he could be cheating on you and just be happy to have an out." Mr. Dirty Bottoms says that the toilet-seat defense is sound, prompting House to finish this subplot off with a simple "She'd only choose to believe a well-presented lie if she were innocent, and since you both can't be innocent, you ruddy jackass..." At which the cuckolded Mrs. Lambert takes off her wedding ring and hurls it down, her husband running after her. Wow. House sure read a lot of Encyclopedia Brown books as a kid. Even Cuddy is impressed. House picks up the wedding ring, considers it for a moment, and quickly drops it on a nearby table, and the writer of this episode turns to all of the friends he invited to his viewing party and announces out loud, "And this is the shot that everyone who watches this is going to think I stole from Match Point."