Derek's sister Nancy (
Embeth Davidtz) pays a visit for the express purpose of giving him Hell about the "slutty" Meredith (
Ellen Pompeo), all the while blissfully ignorant of Addison's infidelity. Cristina (
Sandra Oh) inspires envy when she helps perform a rare cardiac autotransplantation (aka the Humpty Dumpty procedure), but her actions just before surgery serve only to arouse suspicions about Burke (
Isaiah Washington). Addison (
Kate Walsh) and George's (T.R. Knight) pregnant patient Noelle (Liza Lapira) is in a strange predicament: she has two uteruses, and one of her babies is growing faster than the other, indicating that she's been unfaithful to at least one of the fathers. And finally, Alex (
Katherine Heigl) toys with the idea of retiring as a doctor and using her multi-million-dollar inheritance to start another business. ~ Hal Erickson, All Movie Guide