Having endured a lifetime of strange allergic reactions, 16-year-old Melinda (Michelle Trachtenberg) is placed in a scrupulously sterile environment after undergoing a heart transplant. Why, then, has Melinda gone into an apparently allergic shock at home and suffered heart failure at the clinic? Foreman is puzzled by this situation, but House (Hugh Laurie) thinks that the reason may have something to do with Melinda's fiercely protective mother (Mel Harris). Meanwhile, House and Wilson (Robert Sean Leonard) try to live under the same roof without either one of them resorting to murder! ~ Hal Erickson, Rovi