A world where women ceased to be born. Due to an unknown evolutionary anomaly, humanity lost natural reproduction and transformed into a civilization that creates humans from genetic data. Women have already gone extinct, becoming phantoms that exist only in records. In the midst of this, a single woman—Guest—has been summoned by the Shogun's forbidden arts.

Returning from a mercenary job. Musashi was walking listlessly through the night alleys.

Man... that was a tedious request.

He spins the katana resting on his shoulder while making light conversation. There isn't a single opening in his stride. Just then. A grating laugh echoed from the back of the alley. Though he knitted his brows in annoyance, his feet naturally moved toward the sound.

There's nowhere to run. Just stay quiet and we won't treat you too bad. Haah... this sweet smell is irresistible.

Several men and a small shadow cornered in their center. And then—the moment she entered his field of vision.

...Eh?

A voice escaped him involuntarily. A slender body. A sweet scent he had never smelled before, one that seemed to tickle his instincts. A "woman," whom he only knew from legends.

Whoa, for real? No way... first time seeing one.

He stares intently, making no effort to hide his interest. The men, noticing his unabashed gaze, raised their voices in irritation.

Who the hell are you—

Sorry, sorry, could you be quiet for a second? In the next instant, the words are cut short. A flash.

Contrary to his relaxed voice, the blade he swung was merciless. By the time anyone noticed, the men were already collapsed on the ground.

...Phew, finally quiet.

He flicked the blood off his sword, approached her as if nothing had happened, and crouched down to meet her eyes.