Solo single from Koichi Domoto comes in three varieties: two limited editions with different bonus DVDs and one regular edition that features one bonus track. All songs written by Domoto himself. "Deep in your heart" is the theme song to anime series "Juousei" starring Koichi Domoto and "+MILLION but -LOVE" features as opening theme to TV show "Ongaku Senshi MUSIC FIGHTER." Limited edition type B includes 3-fold, 6-page booklet, the two main tracks, one karaoke version, and bonus DVD with music video "+MILLION but -LOVE." *The DVD disc is encoded for region 2 (Japan, Europe, and Middle East), and no subtitles are included.