About Grey's Anatomy Season 4, Episode 17 : Freedom (2)

A couple undergoes surgery. Derek and Meredith's clinical trial gets a second shot from a new patient. Izzie helps Alex. McSteamy hooks up with someone. Guest Stars: Jurnee Smollett, Loretta Devine, Amy Madigan, Lauren Stamile, Sterling Knight, Elizabeth Reaser, John Cothran,