 Wilson is preparing his 14-year-old patient, Nick, for a bone marrow transplant when the donor, Nick s younger brother Matty, suddenly starts sneezing. Since Nick s immune system has been destroyed by the chemotherapy for his cancer, he cannot risk a marrow donation from Matty while Matty is ill. House decides that the fastest way to find out what s wrong with Matty is to make him worse. As the boys get sicker and sicker, House and his team race to cure Matty before both brothers die. Meanwhile, House battles Hector (his newly adopted dog) for supremacy and Foreman can t stop thinking about last week s mistake.