Sage is a thirteen-year-old girl living in Harlem with her father following her parents' divorce. She loves mathematics for its definitive answers and harbors a childhood dream of becoming a pilot. Her daily routine shatters when her best friend dies in a hit-and-run accident on Sage's birthday. Feeling secretly responsible for the timing of the accident, she withdraws from her family and fears the streets of her neighborhood.

Angel was Sage's twelve-year-old best friend who wanted to become a computer coder. She died in a hit-and-run accident on the day of Sage's thirteenth birthday. Though she does not appear in the present timeline, her personality, her fear of roller coasters, and her generous nature heavily influence the story. She leaves behind a grieving family and a bedroom full of untouched mementos.

Aunt Ini is Sage's great-aunt who acts as a grandmother figure to the family. She raised Sage's father after her own sister passed away forty years ago. She carries her own long-term sorrow but uses it to teach Sage that pain and beauty can coexist. She loves visiting the Harlem Meer in Central Park and eagerly tracks the seasonal arrival of tulips.

Ebony is a middle school student who joins Ms. Carver's sessions after her father dies suddenly of a heart attack. She reaches out to Sage with invitations for sleepovers and trips to a Jamaican bakery. She understands the shock of an unexpected death, allowing her to sit with Sage in silence when words fail.

DD is a pragmatic and resilient middle school student whose older brother, Nathan, was killed by police during a traffic stop. She speaks about his death with direct, clinical terminology while simultaneously remembering his humorous quirks. She uses humor to cope and offers sharp, perceptive observations about her peers' behavior.

Ms. Carver is the school counselor who facilitates a support group for five girls processing severe losses. She provides snacks and a structured environment where students can share memories or simply sit quietly. She frequently uses metaphors to explain emotional processes and supplies the students with practical tools, like journals and stress balls.

Sage's father is a divorced parent living in Harlem. Since his older son left for college, he maintains an unusually quiet household and leaves his son's bedroom completely untouched. He tries to establish new routines with his daughter, like watching Friday night basketball games, while giving her physical comfort when she struggles in public.

Sage's mother is a divorced parent who remains closely involved in her daughter's life. She actively encourages Sage to pursue her childhood dream of flying, insisting that she attend the local aviation program. She organizes outings to Times Square to help Sage and her peers enjoy their city as tourists.

Kofi is a teenager who spends time playing basketball in Morningside Park. He pays close attention to the people around him and notices when Sage stops visiting the park. Because he has no connection to the tragedy in Sage's life, he provides her with a space to talk about her memories without judgment or shared trauma.

Ana is a member of the school support group who recently lost her twin sister to leukemia. Because she had time to sit by her sister's hospice bed and say goodbye, her experience of prolonged sorrow contrasts sharply with the sudden tragedies experienced by some of her peers.

Zay is a student attending the support sessions following the death of his grandmother, who passed away in hospice care. He struggles with feelings of guilt because her passing freed up his family's time, introducing complicated feelings of relief into his mourning process.

Spencer is Sage's older brother who attends Howard University. During his parents' divorce, he was already away at school and therefore drifts between his parents' homes when he visits. His departure leaves a noticeable quiet in his father's house, as he used to initiate rap battles and yell during basketball games.

Mr. Dixon is Sage's math teacher whose classroom is chaotic but organized. He uses geometry, specifically lessons on parallel and transversal lines, to explain how human lives intersect temporarily but meaningfully. His subject provides Sage with a sense of comfort due to its definite formulas and correct answers.

Ms. Barbara is the instructor for the Fly Girl youth aviation program. She teaches her students the technical aspects of flight while acknowledging that some scientific questions lack complete answers. She uses the mechanics of airplanes to offer practical advice on handling life's turbulence.

Brielle is Angel's older sister. She used to chaperone Angel and Sage during their childhood park visits. She acts as a bridge between Sage and the Rodriguez family, eventually arriving at Sage's door to deliver a recovered item from the accident site.

Angel's mother is a grieving parent who treats Sage as a bonus family member. Despite looking frail following the death of her youngest daughter, she maintains a kind demeanor and preserves all of her daughter's belongings, offering Sage the chance to take home keepsakes.

Nathan was DD's older brother who was killed by police during a traffic stop when an officer mistook his asthma inhaler for a weapon. While the public nature of his death ties his family to a larger history of injustice, his memorial service focuses entirely on his humor, his personality, and the joy he brought to others.

Fatoumata is a student enrolled in the weekend aviation class alongside Sage. She is curious about the broader logistics of the airline industry and prompts the instructor to explain the various roles required to operate a commercial flight.