Merci is an eleven-year-old Cuban-American girl attending the affluent Seaward Pines Academy on a scholarship. She is highly athletic and dreams of playing on the school soccer team, but she struggles to maintain the grades required to keep her funding. She feels self-conscious about her amblyopic eye and her financial status, preferring hands-on work and often making plans to skip college to take over her father's painting business.

Lolo is Merci's grandfather who lives in the middle house of the family's property, Las Casitas. He acts as Merci's closest confidant, sharing afternoon snacks and weekend bicycle rides with her. He is experiencing early stages of memory loss and confusion but stubbornly insists on hiding these struggles from his granddaughter to protect her childhood.

Roli is Merci's seventeen-year-old brother and a fellow scholarship student at Seaward Pines Academy. He maintains top grades with ease and spends his required community service hours working as a science lab assistant. He approaches life with a scientific, rational mindset and acts as an intellectual voice of reason for his younger sister.

Abuela is the matriarch of the Suárez family. She serves as the family's informal catastrophic concerns manager, constantly pointing out everyday hazards and worrying about her relatives' safety. She is a highly skilled seamstress who uses her talents to create elaborate clothing and costumes for her grandchildren.

Edna is an affluent and popular student at Seaward Pines Academy. She uses her family's wealth, her stylish appearance, and her assertive personality to dominate her social circle. She frequently brags about her father's successful medical practice and actively targets Merci with rude comments about her clothes and interests.

Ana is Merci's mother, working as a busy physical therapist at local rehabilitation centers. She maintains a persistent optimism that sometimes frustrates her daughter. She relies heavily on her extended family to help manage childcare and the complex logistics of daily life.

Enrique is Merci's father and the hardworking owner of a local painting business called Sol Painting. He plays in a community soccer league where he occasionally lets Merci take the field with the adult men. He is strict about the family rule against lying and continuously reminds Merci that her scholarship requires exemplary behavior.

Tía Inés is Merci's aunt who manages a local Cuban cafe called El Caribe. She shares the Las Casitas property with her extended family and depends on them to help watch her rambunctious twin boys. She has recently gone through a divorce and focuses heavily on keeping her household running smoothly.

Michael is a new student at Seaward Pines Academy who recently moved from Minnesota. He is exceptionally tall and pale, trying to adjust to the new school environment while unintentionally drawing romantic interest from the popular girls. He depends on Merci to show him the ropes around campus.

Miss McDaniels is the school secretary and guidance teacher who manages the student ambassador program. She runs a tight ship and strictly enforces school rules. She assigns Merci to be a mentor to a new student and refuses to entertain requests for a reassignment.

Jamie is a student at Seaward Pines Academy and acts as a loyal sidekick to Edna. She follows the popular crowd in social situations, mirroring fashion choices and participating in efforts to exclude other girls from their circle.

Ms. Tannenbaum is a popular social studies teacher who wears casual clothing and has unruly hair. She encourages creativity and teamwork in her assignments, leading large projects like transforming the classroom into an ancient tomb.

Hannah is a classmate of Merci's at Seaward Pines Academy. Though she initially spends time with the popular crowd, she shows independent thought by supporting Merci's creative ideas during group projects and trying to find fair compromises.

Lena is a quiet student at Seaward Pines Academy who sports a spiky haircut with blue-dyed tips. She typically eats lunch by herself and has a strong artistic background that proves useful in school projects.

Axel is one of Merci's young twin cousins. He lives in the rightmost house of the family property with his mother and brother. He is highly energetic, frequently running wild around the neighborhood and requiring constant supervision.

Tomás is the other young twin cousin living on the family property. Like his brother, he is boisterous and prone to making messes, such as painting the exterior walls with plain water. He often clashes with Merci when she is assigned to watch him.