Yuusuke Yotsuya wants nothing more than to be left alone, so being summoned into a game-like fantasy world alongside two classmates by a faceless, mask-wearing entity is his worst-case scenario. The three must clear assigned quests to earn the right to respawn after death, and each cleared round conscripts another player into the group, with the lives of a million inhabitants of that world riding on how they perform. Alongside teammates Iu Shindou and Kusue Hakozaki, Yuusuke turns pragmatic and calculating to keep the group alive through missions with no safety net.