Sure enough, House holes himself up in a shower stall with some kind of blue light, which causes the dosimeter to turn red. I don't know a lot about dosimeters, but I'm going to assume that's a bad thing. He then scratches Wilson's name off of it.
Over in the NICU, Taub's blood isn't making the baby any better, which rules out Cheng's deficiency diagnosis. Taub tells Abbey that they'll focus on infections instead, and she tells him why she decided to have the baby in the first place, like anyone cares. I'm fine with assuming it's because her first kid turned out so awful. She says she wanted to be a "special mom," whatever that means.
Cuddy breezes into House's office complaining of problems in radiology by way of a positive radiation dosimeter badge, which means there could be a radiation leak somewhere. Also, Cuddy says, the name on the badge was scratched off, so she doesn't even know who the badge belonged to, nor does she find this suspicious. Thus, Cuddy says, she has to stay late and is hoping House can baby-sit for Rachel again. He pretends to hate this idea and agrees to it only when Cuddy promises sex in return. When she leaves, House smiles to himself about how well this is all working out. I'm just looking forward to this sitcom storyline ending already.
Taub sticks a giant needle into the baby's liver to get some infection material to test, but a black fluid fills the syringe instead of the pus he and Foreman were expecting. Abbey asks what that is, and Foreman tells her it's not an infection after all, but skin cancer. Which can apparently be inside your liver. And full of black goo. Abbey is understandably confused as to how her baby could have skin cancer without ever having been in the sun. "You have," Taub says. Yes, Abbey is the one with skin cancer, and she gave it to her daughter while she was in utero. Great, that's another thing for Justine to be jealous of.
After the break, Taub exposits that he found the cancerous mole under one of Abbey's fingernails. Oh, and now Cheng gets to sit at the meeting room table, which is covered in everyone's food orders. Except for House's, as no one got him anything. House says if Abbey has melanoma, then "that's it." Cheng says that's not exactly right, since Abbey can kind of die and stuff. "Boring," House says. What he does find interesting is the fact that for the cancer to spread to the baby in utero, it would have to be metastasic and late-stage, but Abbey doesn't appear sick at all. Foreman says whatever it is in Abbey's blood that's treating her baby, it must be treating her, too. Her immune system is fighting something else, thus creating cancer-fighting antibodies. Foreman, Chase, and Cheng come up with a few suggestions. House sends Taub off to test Abbey for an autoimmune disease, hoping he'll leave his dinner behind for House to eat. He does not.