After rescuing his master, Rias Gremory, from the Dimensional Gap, Red Dragon Emperor and aspiring Harem King Issei Hyoudou can finally daily resume his high‑school life together with the other members of the Occult Research Club—Yuuto Kiba, Asia Argento, Xenovia Quarta and Irina Shidou. The group soon sets off on a school excursion to Kyoto.
While peacefully touring a temple under Rias" protective charm, an attacking band of local youkai disrupts the serenity. When the clash ends, the club discovers that the legendary nine‑tailed fox guarding the city has been kidnapped and that someone has framed them for the crime. Issei and his friends must now battle to safeguard the city and rescue their trip from a looming catastrophe!
Meanwhile, Rias—who must remain in Tokyo with Akeno Himejima and Koneko Toujou—feels increasingly uneasy about leaving Issei alone with the other girls of the Occult Research Club. Beyond this vague unease, what specific emotions has Rias been wrestling with over the past few months, including the tension between duty and personal desire and the looming threat of a supernatural disaster?
