Nijiiro Days follows the colorful lives and romantic relationships of four high school boys—Natsuki Hashiba, a dreamer with delusions of love; Tomoya Matsunaga, a narcissistic playboy who has multiple girlfriends; Keiichi Katakura, a kinky sadist who always carries a whip; and Tsuyoshi Naoe, an otaku who has a cosplaying girlfriend.

• Shochiku
• Reo Sano
• Taishi Nakagawa
• Mahiro Takasugi
• Ryusei Yokohama
• Ai Yoshikawa
• Yuri Tsunematsu
• Mayu Hotta
• Nozomi Bando