The story takes place in a martial arts training school called "Koryu Gakuen". Kokonoe Toru (voiced by Matsuoka Yoshitsugu), who has a tragic past, comes here with a heart full of anger and ambition, hoping to hone his skills here and become strong to avenge his dead sister. A special system called "Bond Twin Blades" is implemented on campus, where students must form a bond twin blade in pairs, eat and live together to deepen their bond. The deeper the bond, the stronger the power the two gain. On campus, Kokonoe Toru meets a Nordic girl named Julie (voiced by Yamamoto Nozomi), and the two form a bond and start living together. In addition, the arrogant and willful Lilith (voiced by Yamazaki Haruka), the slow and honest Tachibana (voiced by Suwa Ayaka), and the weak Hodaka Masa (played by Imamura Ayaka), these lovely girls will find their lifelong bonds in school.