An elite player is summoned by two maidens to save a fantasy game.

Within the world of Cross Reverie, two maidens in dire need summon the fearsome Demon Lord Diablo to save them. But Cross Reverie is just a virtual reality game, and Diablo is Takuma Sakamoto, an elite player with social issues. Sakamoto is shocked at his situation, even more so when the maidens Shera and Rem become magically enslaved to him, but he decides to rise to the occasion and use his Diablo persona to help out the girls and survive in the new world.