Matty undergoes being made really cold. He complains to his mother that he's freezing, but she doesn't care. Meanwhile, Nick's every need is no doubt being taken care of. Chase and Foreman enter to ask Matty if he's ever taken a drink from the water pump. Matty says he has, and that the water was "really gross"...but that was all the way back last summer, so it's not relevant now. Matty reports that his arm is sore, but Chase and Foreman think it's just a muscle strain from pitching practice. Matty has another problem to report, but he wants his mother to leave the room before he does it. And, presumably, the female nurse throwing ice water on him will have to leave, too.
Foreman tells House what's up: Matty has "acute scrotum." House, of course, makes the necessary joke about cute scrotums, then says big balls (acute scrotum is described as a painful swelling of the scrotum "or its contents," which doesn't sound like fun at all) are a good symptom because relatively few infections cause them. House pauses to give the male audience time to breathe a collective sigh of relief, then tells Foreman to get cracking with a bunch of tests. Foreman asks if Chase and Cameron can do them instead while he checks the marrow donor registry for an alternate donor in case their plan fails and Matty can't donate the bone marrow. Surprisingly, House agrees.
Cameron and Chase do the tests, although not without whining from Cameron about how House is giving Foreman a break and waah waah wahhhh it's not fair. Chase changes the subject to the fact that today is Tuesday, which means he's telling her that he likes her and wants them to be together. "Thank you. I'd forgotten," Cameron replies coldly. Oh, go die alone, Cameron. How can you resist that? And even if you can, why resist so angrily? I guess I wouldn't mind it so much if she hadn't been so cruel to him the first time he said he had feelings for her. It's not like she was ever nice to him about it and is only now being mean because she's sick of his persistence. The thought of Chase having feelings for her has always made Cameron ridiculously angry. Chase goes back to work, but Cameron would rather yell at him for being adorable than help save a child's life. So, while Chase wonders if they should be looking for an infection that caused something that caused the scrotum issue as opposed to searching for an infection that caused the scrotum issue, Cameron keeps bringing his Tuesday reminder thing up. Then Chase notes that the CK-MB levels in Matty's blood are up, indicating a possible heart infection.