When an ex-con is mysteriously slain in an alley, Castle and Beckett believe a vigilante is behind the murder. But efforts to identify their suspect are thwarted when they discover that he roams the city in a Superhero costume -- and may indeed be a Superhero. Can they capture and unmask the killer before he strikes again?
Elenco: Nathan Fillion , Stana Katic , Susan Sullivan , Seamus Dever , Jon Huertas , Molly C. Quinn , Tamala Jones , Toks Olagundoye , Seamus Dever , Susan Sullivan , Tamala Jones .