Yiyun Li is a writer, mother, and MacArthur Fellowship recipient attempting to establish a framework for living following the suicides of her sons, Vincent and James. Drawing from her own history with severe depression and a traumatic childhood in China, she actively rejects standard cultural narratives of mourning. She relies instead on literature, philosophy, and "radical acceptance" to confront her reality. She uses disciplined, intellectual practices, such as studying Euclid's geometry and playing mechanical piano exercises, to fill her days and mark time.

Vincent is Li's flamboyant, artistic elder son who lived life intensely and "feelingly." A perfectionist who loved language, beauty, and poetry, he possessed a theatrical personality, once wearing a pink dress to middle school to assert his identity. His brilliant, expressive nature coexisted with a deep internal despair that caused his mother years of dread.

James is Li's quiet, logical, and intensely private younger son. He lives "thinkingly," possessing a formidable intellect that draws him to complex scientific concepts and the philosophy of Wittgenstein and Camus. Preferring to remain unnoticed, his stoic exterior shields a deep internal anxiety and a lifelong fear of being alone.

Yiyun Li's Mother is a volatile figure from the author's past who subjected Li to severe physical and emotional abuse. She frequently used psychological manipulation, such as comparing Li to an imaginary, perfect twin, and physically attacked her for minor perceived infractions. She currently denies her history of abuse, claiming her daughter fabricates the stories for fiction.

Brigid is Li's closest friend of over twenty years and her first reader. She possesses a rational, clear-eyed understanding of Li's mind and work. In moments of crisis, Brigid provides indispensable support, intervening to keep the family grounded in reality and helping Li distinguish between meaningless anxieties and true facts.

Li's husband is a steady presence who shares her commitment to creating a safe, respectful home for their children. He holds a deep respect for personal free will, a philosophy that informs his understanding of his sons' tragic choices. He partners with Li in enduring the reality of their permanent loss.

Christiane is a linguistics professor who previously taught James. She displays moral courage by sending Li a direct, honest message that acknowledges James's desire to leave the world, offering quiet and respectful company during the family's darkest period.

Deborah is a writer friend of Li's who offers sharp, unsentimental advice. When Li questions if anyone will understand her intellectual approach to her reality, Deborah quickly dismisses this doubt by quoting poetry and demanding courage.

Cristina is a piano teacher who instructs Li in mechanical finger drills. She is astonished by Li's insistence on attending lessons immediately following James's death, not realizing that the structured routine is a necessary survival mechanism.

Tom is a fellow writer who visited Li during her severe depression. He provided a vital mental refuge by bringing her books by Tolstoy and Montaigne, helping her engage her thinking mind when she was trapped in a chaotic hospital environment.

Katherine is a friend who possesses the courage to ask direct, challenging questions about the deaths of Li's sons. Her inquiries prompt Li to formally examine the philosophical differences between Vincent's and James's final choices.

Quintus is the family dog, named by Vincent. Following Vincent's death, Quintus becomes a quiet recipient of James's private anguish as the family attempts to adjust to their altered reality.