On Monday night's much-anticipated wedding episode of Castle, Rick reveals his plus-one: "She's beautiful. She's intelligent. She's funny. The way she smiles at me sometimes melts my heart." Watch the clip to find out who "she" is!Original Air Date: Castle Season 4, Episode 11: "Till Death Do Us Part" airs on Monday, January 9, 2012 at 10 p.m. ET on ABC.