A 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? Season 4, Episode 2 of Castle airs on September 26th, right after Season 4 Episode 1’s air date, which is on September 19th. Castle is aired on Mondays at 10/9c on ABC. Everyone, look forward to the day Castle Season 4 airs!