Grey's Anatomy season 5 began normal enough (Cristina caught the eye of an attractive military doctor named Owen, Meredith and Derek worked to recapture their spark) but a few episodes in, Izzy's hallucinations of Denny — often referred to as the ''ghost Denny'' period — proved too much for some viewers. According to an EW poll, many took it as a cue to jump ship. Our plea? COME BACK! We recognize catching up is a tall order, but here is our handy-dandy guide to everything you'd have missed since that arc.