One day, high school student Haruki Ito, along with his entire class and teacher, is suddenly summoned to another world. Upon arrival, the summoned students are inexplicably confined in prison cells in male-female pairs and are subtly coerced into having physical relationships. Haruki is paired with Shizuka Inoue, a girl who usually acts plain and unassuming but is actually a hidden beauty.

The male students are eventually released from their cells, but the kingdom holds their female partners hostage to force the boys to subjugate monsters for the nation's benefit. For Shizuka's sake, Haruki reluctantly begins training and fighting. As he continues his monster-hunting duties, he gradually realizes that something is different. He wonders if he has become incredibly powerful, and soon discovers the nature of the unique ability he has acquired: the authority to cut absolutely anything. This power turns what should have been a desperate struggle into what feels like an easy mode for the summoned hero.

The story follows Haruki as he comes to terms with his overwhelming cheat skill. His ability to cut anything, even abstract concepts, makes missions trivial. As he completes tasks with ease, he cherishes the moments he gets to spend with his partner, Shizuka. However, a completely peaceful life proves difficult. Despite Haruki's desire to live quietly, his immense power attracts trouble. Observers note that his strength is not just special but on a level where he alone could destroy an entire country. As the narrative progresses, Haruki's power becomes intertwined with Shizuka's fate, as the authority of the one who can cut everything is eventually passed to or shared with her, transforming her into a formidable warrior as well. This development creates a dynamic where the pair, now both incredibly powerful, must face the escalating troubles that come their way.