While visiting a store in Landosol, Yuuki and Kokkoro encounter Aoi wearing an unfamiliar uniform. It turns out that Aoi is a new student at the prestigious St. Theresa's Academy for Girls, but is worried she won't be able to fit in. Thus Yuuki and Kokkoro head to the school with her as moral support.

Recently, a mysterious knight has been appearing around Landosol and harming the residents. Inspired by Pecorine, who is angry that the people won't be able to enjoy their delicious food, the Gourmet Guild takes on a quest to defeat the culprit. Along the way, they meet a small girl who calls herself a soldier.

When an injured Miyako and Shinobu show up at the Gourmet Guild, Pecorine and company are shocked to learn that Diabolos has been attacked, and its members have been kidnapped. As Shinobu explains that the assailant was someone they never would have expected, there is a loud rumbling that shakes all of Landosol...