Keiichi Naruse is a single father raising his young son Ichika Naruse alone, juggling full-time work with childcare duties and leaving scant personal time. His past includes a volatile marriage; he left Ichika's mother when she resorted to physical violence against their crying infant son, prioritizing Ichika's safety above all. This cemented his commitment to being a protective and nurturing parent.

He hires male college student Kōya Asumi as a housekeeper for domestic tasks like cooking and cleaning, following issues with previous female housekeepers. Physically, Keiichi is a handsome young man with brown hair, ochre eyes, and a height of 173 cm. He typically wears casual loungewear, including slippers. His personality blends parental dedication with underlying loneliness and unmet needs, prompting him to keep adult magazines and videos in his room for private gratification.

Keiichi displays embarrassment when these materials are discovered, making flustered attempts to hide them. This vulnerability creates an opening for Asumi to initiate physical contact. Early encounters feature advances during Keiichi's flustered or surprised states, raising questions of consent. Over time, he grows more receptive to Asumi's overtures, developing mutual feelings despite initial reservations. Their relationship evolves from employer-employee dynamics into a romantic and sexual partnership, deepening through shared moments and physical intimacy.

He faces societal challenges as a single father, including judgment and gossip from mothers of Ichika's classmates. His commitment to providing Ichika a stable, loving environment remains central. The relationship with Asumi navigates homophobia and redefines family structure, culminating in a committed partnership where Asumi integrates into their household. Keiichi's development shows a shift from emotional restraint toward accepting support and affection, balancing fatherhood with personal desires.