the series' original soundtrack was released as "spiral melodies" on october 24, 2007 by aniplex. two singles, "gun's & roses" by paradise lunch and "calling" by kaori oda, were released on august 22, 2007. "gun's and roses" contained the opening theme, a vocal version of the opening, two songs and karaoke versions of the three tracks. the "calling" single included the ending theme, another track and the karaoke versions of the two.