During the era of Westward expansion. Lin, who abandoned her identity as a woman, chose the path of living as a gunslinger. Riding her beloved horse, she continued her aimless journey, taking down men who bared their fangs the moment they saw her voluptuous chest, using her exceptional gun skills. However, a fierce fate stands in her way.

BOOB SLINGER

Team Big Summer conducts psychic investigations on a daily basis. Momoka, a member of the team who is fed up with ghosts, proposes a "boyfriend audition" as a YouTube project. Komori, Cheokayama, and Onaga came to the audition. Momoka did not get a boyfriend on the show, but she and Momoka had been out of touch since then.