Kōshi Shirota is the male protagonist of the series. He is an ordinary high school student who lacks social standing and is often overlooked by his peers. His life changes dramatically when he accidentally witnesses student council president Takane Takamine changing clothes and discovers her secret ability, known as Eternal Virgin Road. This power allows Takane to rewind time by removing a piece of her underwear, but because Shirota saw her naked, he is the only person who can retain the memories of the rewound timeline and accompany her through the time reversal.

Initially forced into the role of her personal closet—responsible for carrying spare lingerie and replacing it after each use—Shirota’s cooperation is secured through blackmail, as Takane threatens to falsely accuse him of sexual assault. His early motivation is purely self-preservation, avoiding criminalization and public ruin. Over time, however, he begins to take his task seriously, growing determined to protect Takane from embarrassment and to help her maintain her perfect reputation. He later reflects that he was unaware of her romantic intentions toward him during this period.

Personality-wise, Shirota is mild-mannered and describes himself as having a weak will, but he displays growing reliability and a sense of duty. His development sees him move from a reluctant pawn into a more proactive and caring partner, even as he remains bewildered by the bizarre circumstances. His key relationship is with Takane Takamine, a dynamic built on coercion and secrecy that gradually deepens into genuine trust and affection. Notably, Shirota’s ability to remember the rewound moments and physically travel back in time with Takane is unique and essential to the functioning of her power, making his role central to the story.