Plot: Meredith grows increasingly dissatisfied with the unknown details of Derek's life. Meanwhile, Alex treats Devo, a patient whose religious beliefs jeopardize her chances for recovery; Izzie contemplates reconnecting with her estranged mother; Zoey, a pregnant woman in her 40s who's been diagnosed with cancer, disagrees with Cristina's medical advice; and the interns are mystified by Cable, a patient who's being treated for seizures and who thinks he's psychic