Sora and Shiro have been abandoned in another world by Tet. In this world all war is forbidden, and everything is determined by games whose rules are determined by the "Ten Pledges" that Tet established. They find themselves in the country of humanity, the weakest of the 16 races in this new world.

The game Clamy challenged them to wasn't normal chess. Shiro is a chess master, but even she is helpless against Clami's assault. But when Shiro understands the real rules of the game, things begind to turn around. The battle to determine the king of Elukia, and all of humanity, finally reaches its end.

Intending to challenge the Werebeasts, the siblings discover that it's hard to come with a strategy to defeat the latter, as all memories regarding the games are erased from their challengers, until Stephanie entrusts Sora a key left by the former king, leading to his secret research on how to outwit them.

Sora, Shiro, Steph and Jibril devise a risky plan with even riskier stakes, making their way to the Warbeast embassy to challenge them.

While Izuna's abilities seemingly defy physics, Sora and Shiro make potentially futile attempts to amp up their game.