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.

A healer gets booted from his party because the leader notices he isn't really contributing much to the team. Soon enough, the healer must look for new members to party with. After finding a cute martial artist to work together with, he reveals his secret: while he's a fairly mediocre healer, he actually fights well in close combat. This is the story of a support who's secretly a DPS, and where the entire conflict stems from the fact that he never told his old party he was a DPS. (Source: MU)