"Ane wa Yome" centers on the unconventional relationship between a young man named Shou and his older sister, Aki. After the death of their parents, Aki takes on the responsibility of raising Shou, and the two develop a close bond. However, as Shou grows older, his feelings for Aki evolve beyond familial love, leading to a complex dynamic between them. Aki, who is pragmatic and protective, struggles to reconcile her role as a caregiver with Shou's growing romantic attachment. The narrative explores themes of familial duty, emotional boundaries, and the blurred lines between love and obligation.

The story progresses as Shou openly confesses his feelings to Aki, creating tension and forcing both characters to confront their emotions. Aki, while initially resistant, begins to question her own feelings and the societal norms that dictate their relationship. The manga delves into their internal conflicts, portraying Aki's struggle to maintain her role as a responsible older sister while grappling with her own vulnerabilities. Shou, on the other hand, is depicted as determined yet naive, driven by his unwavering affection for Aki.

Secondary characters, such as friends and acquaintances, occasionally appear to provide external perspectives or complicate the central relationship. These interactions highlight the societal pressures and judgments faced by the protagonists, adding depth to the narrative. The manga balances moments of emotional intensity with lighter, everyday scenes, creating a nuanced portrayal of the characters' lives.

The plot unfolds through a series of intimate and often introspective moments, focusing on the evolving relationship between Shou and Aki. Their journey is marked by moments of hesitation, self-discovery, and gradual acceptance of their feelings. The story does not shy away from exploring the moral and emotional complexities of their situation, presenting a thought-provoking examination of love, family, and societal expectations.