The story takes place in Japan. The year is 2030 and Earth has been completely overrun by a viral disease named "Gibia" that turns infected people into various different monsters, based on their age, sex, and race. A samurai and a ninja from the early Edo period travel together through time and arrive in a ruined Japan to aid a professor working on a cure for the virus. Together, they fight countless Gibia monsters, outlaws, and other fierce foes on their journey to save mankind.

Gibiate was created by GIBIATE Project, a global IP development group consisting of internationally renowned Japanese creators such as Yoshitaka Amano ("Final Fantasy"), Naoki Serizawa ("Biohazard" / "Resident Evil"), Yuzo Koshiro (composer of "Ys" and "Act Raiser"), Yoshida Brothers (world-renowned shamisenist group) and SUGIZO (guitarist from LUNA SEA/X JAPAN).