Ritsu Tainaka, the drummer of the band of Houkago Tea Time, had made a promise to a classmate during her middle school. What if they started living under the same roof due a teacher's request? Will they get along and fulfill the promise that they made in the future? Find out! (RitsuXOC) Changed Rating to T for swearing, yandere references, and slight hentai.

A 'what if' story about Mikoto, Touma, Misaki, and other two girls being childhood friends. Even after 10 years, they never change. Watch how the five fight together to save Academy City in peace. Rated T for slight violence. Some characters are a bit OOC, Mikoto and Touma being that close, Kuroko accepting her onee-sama's love for Touma, and Misaki being a bit reckless!