GREY'S ANATOMY - "Shiny Happy People" - An elderly patient admitted into the E.R. for a heart condition sees a familiar face, a long lost love who happens to be in the E.R. as well for a fractured arm, and the staff find themselves caught up in their love story. Meanwhile, Karev treats a troubled teenage patient (guest star Demi Lovato) whose parents brought her in for schizophrenia, and Meredith can't help but tell Cristina about her suspicions of Owen -- which inevitably messes with Cristina's head -- on "Grey's Anatomy," THURSDAY, MAY 13 (9:00-10:01 p.m., ET) on the ABC Television Network. (ABC/MITCH HADDAD) JAMES PICKENS, JR., KEVIN MCKIDD