Tragedy strikes when Derek loses a pregnant patient with an aneurysm during surgery and Addison must deliver the premature baby; Izzie learns she does not have anemia as she first thought, but something much worse.
Derek searches for the best way to propose to Meredith; Callie tries to convince Mark not to blow his chance at real love with Lexie, despite his fear of Derek finding out; Izzie learns she has anemia.
When a homeless woman goes missing from a shelter linked to a previous case, Jack suspects Rick Knowles -one of two identical twins--who manipulated his brother, Greg, into confessing to the murders of several other homeless women.
Reports of Frasier's death are greatly exaggerated. Nonetheless, he's disappointed to realise that he hasn't achieved what he'd set out to in life. Meanwhile, Niles decides to settle a score with a plastic surgeon and is shocked to find out he is attracted to her.
A college football player collapses in the heat of practice and his death haunts Nate with his AVM secret. With Matt Gilardi failing to buy out the resilient Fishers, Kroehner's regional director decides to take matters into her own hands.