Yuuji Kazami and his friends Michiru Matsushima, Makina Irisu, Sachi Komine, Amane Suou, Yumiko Sakaki, Kazuki Kazami, JB, Principal Tachibana, and Chiara Farrell teaming up to find clues from their past, before the evil Rasputin Oslo and his sidekick Bat an albino Canary to destroy their future, They return to Mihama Academy to encounter Rena Fukami, Haruto Aoi and the rest of the cast from "Grisaia Phantom Trigger" and others like the cast from "Grisaia Chronos Rebellion" find the secret about the Mihama life, travel to Yokohama to think about Yuuji and the gang's memories, later Travel to Tokyo to found their secret.
