The protagonist is summoned to a fantasy world to resist the demon lord’s invasion. Upon arrival, they receive an unusual and powerful skill called “World Alteration (R18)” — a SSR-level ability that allows them to copy other characters’ powers by “conquering” them, with hints toward adult-themed “R-rated game-like” conquest mechanics.

Suddenly the fantasy adventure becomes oddly meta-game-like: characters and scenarios resemble galge (dating sim) mechanics, and the protagonist realizes they can rewind time to previous points by conquering targets — effectively turning the narrative into a harem-style fantasy full of battle, attraction, and powers.