Shiori Kanuma, younger sister to ex-Shinogara assassin Hayate Kanuma, becomes an unwilling vessel for her brother’s soul after he mortally wounds himself assassinating their father, the Shinogara’s ruthless leader. Hayate’s consciousness now surfaces within her during confrontations with Shinogara agents, granting Shiori access to his lethal skills at a dire cost: each awakening fractures her identity, leaching fragments of her memories and autonomy. Their symbiotic existence hinges on a shared vendetta to dismantle the shadowy organization that shaped them, yet Shiori’s fading grasp on her own mind casts uncertainty over their crusade. The original 1991 OVA series depicts their precarious alliance and the escalating repercussions of the soul transfer, culminating in an unresolved struggle where Shiori’s survival and selfhood hang in balance.