Japanese anime television series produced by A-1 Pictures and directed by Tatsuyuki Nagai. The anime aired in Fuji TV's noitamina block between April and June 2011. The anime is licensed in North America by NIS America. An anime film was released in Japanese theaters on August 31, 2013, and a second film will be released in 2015. A novelization by Mari Okada was serialized in Media Factory's Da Vinci magazine from March to July 2011. A manga adaptation illustrated by Mitsu Izumi began serialization in the May 2012 issue of Shueisha's Jump Square magazine. A visual noveladaptation for the PlayStation Portable was released by 5pb. in August 2012.