Masanosuke "Masa" Akitsu is a wandering ronin adrift in Japan's peaceful Edo period. Despite being a skilled swordsman, Masa's meek personality has netted him the label "unreliable," and he is often abruptly dismissed by his employers, leading him to question his resolve as a samurai.

As Masa reaches his lowest point, he is approached by Yaichi, a carefree man draped in pink who seemingly hires him on a whim as his bodyguard. Unbeknownst to Masa, the job is not as innocent as it seems, and he is drawn into the illicit activities of the group spearheaded by Yaichi. As he becomes further entwined with the gang known as the Five Leaves, Masa struggles with his own principles. Still, his curiosity spurs him forward to uncover the past and motivations of this mysterious band of outlaws.