Shi Miao stands as a central figure and the younger sister in the primary sibling duo, with her older brother named Shi Fen. Her full name is Shi Miao (时秒), also rendered as Shīmyo (シーミョ) in Japanese. She attends middle school as a third-year student, while her brother advances to high school. Academically challenged, Shi Miao struggles in her studies but demonstrates exceptional athletic ability, making sports her notable specialty.

She possesses a volatile temperament, frequently erupting into violent outbursts directed at Shi Fen, usually triggered by his teasing or actions she deems idiotic. Their daily interactions are defined by relentless bickering and physical altercations. Despite this combative exterior, Shi Miao harbors deep concern for her brother and actively supports him during difficulties, revealing an underlying loyalty. This protective nature extends beyond family; she readily defends friends against bullies through direct intervention.

Miaomiao is acknowledged as Shi Miao's closest friend, forming a significant bond through shared interests like anime and manga. Romantically, Shi Miao develops feelings for Zhen Kaixin, her brother's best friend. Conversely, the wealthy transfer student Wan Sui develops an interest in her, though the narrative does not detail her reciprocation.

Character development occurs as Shi Miao navigates academic pressures and romantic pursuits, facilitating gradual maturation centered on themes of familial loyalty. Key lessons involve understanding the enduring significance of family bonds and the importance of forgiveness, often learned amidst conflicts with Shi Fen. While their relationship remains contentious, moments arise where his protective actions as an older brother soften her stance, allowing subtle shifts in her perspective. Her journey reflects a negotiation between fiery independence and the complex, inescapable ties of siblinghood.