2x12 Grandma Got Run Over by a Reindeer
A young boy needs a heart transplant but doesn't seem to want it, and an argument over his treatment exposes major philosophical differences between Burke and Cristina -- he's spiritual, she's not. Burke won't operate on the boy until his mind accepts the heart, because he believes the body will reject it if he doesn't. Cristina, though not a believer, makes a connection with the kid over their shared skepticism, and gets the boy to want the heart. Meanwhile, when the interns rally to help Alex prepare to re-take his exam, Izzie feels betrayed (after all, Alex just cheated on her). Meredith has to remind Izzie of the true spirit of the Christmas holiday.