Haruto Makabe resides with his older sister Arisa Makabe, his daily life defined by routine chores and errands like returning rented DVDs and washing underwear under her direction. This establishes a domestic dynamic where he passively follows her instructions.

Arisa initiates erotic games with him, leading Haruto to experience escalating astonishment as she consistently pushes boundaries beyond his expectations. Unaware of how this situation will conclude, he faces uncertainty about their relationship's trajectory. His character arc shifts from passive acceptance to heightened awareness of the changing dynamics, though Arisa's actions drive the progression rather than his own agency.

Haruto's background and development remain confined within this singular narrative framework, without canonical expansions. His portrayal centers entirely on reactive responses to the evolving circumstances with his sister.