Leonardo is a dedicated high school history teacher who has recently written a self-published novel, Seventh City. Growing up in a Texas trailer park and raised by his aunt and uncle, his difficult childhood left him with a deep fear of abandonment. He emotionally withdraws from his family, a distance that culminates in his request for a divorce right as a fire destroys their home in Argyle, Texas.

April is a 34-year-old former tutor who left her career to raise her two young children. Struggling with feelings of isolation and a diminishing sense of identity, she bears the weight of a fracturing marriage and unspoken resentments. She acts as the keeper of her family's history, instinctively saving a copy of her husband's novel from the flames.

Deb is the pragmatic and fiercely devoted matriarch of the Russo family. Having served as a caretaker since her youth, she anchors her family from their large home on Lexington Avenue in Dallas. As her children take refuge under her roof, she balances their crises with her own private concerns about her husband's noticeable cognitive decline.

Billy is a successful dentist and the good-natured patriarch of the Russo family. Known for his gentle humor and steadfast loyalty, he provides a stable, traditional father figure for his children. He begins experiencing severe memory loss, leading to an early-onset Alzheimer's diagnosis that alters his family's future.

Josie is April's sister and a traveling theater actress. Dramatic, expressive, and perceptive, she often serves as the catalyst for uncomfortable conversations within the family. Her return to the Russo household forces the family to confront the unspoken tension between April and Leo.

Cameron is April and Josie's brother, providing a quiet and steady presence during the family's chaos. Pragmatic and thoughtful, he follows a traditional life path and frequently steps into a problem-solving role as his parents face new health challenges.

Ricardo, known as Rico, is Leo's estranged father who abandoned him during childhood. For much of the story, he exists primarily in Leo's memories as a source of deep, unresolved pain. Burdened by a history of poverty and grief, his past choices cast a long shadow over his son's adult life.

Sadie is the young daughter of April and Leo. Following the traumatic loss of her home, she struggles to adjust to her family's new living arrangements and develops a visceral fear of fire, reflecting the instability of her parents' relationship.

Otto is April and Leo's infant son. Unaware of the complex emotional and logistical crises unfolding around him, his presence is a constant reminder of the young family's stakes and the need for stability.

Rachel is Cameron's supportive girlfriend and recent fiancée. Coming from a privileged background similar to the Russos, she enters the family dynamic during a period of intense turmoil, bringing both joy through her engagement and new complexities to the crowded household.

Jonathan is a former high school student who struggled with dyslexia. Tutored by April and taught by Leo, he shares a lasting bond with the couple. He eventually authors a novel titled Identity that resonates deeply with his former teachers.

Cody is a confident and wealthy district literacy coordinator who hires April to return to work part-time. He provides her with a sense of purpose and validation during a period of intense personal isolation.

Ana is Leo's mother, who lived with her family in a trailer park in Odessa, Texas, during his early childhood. Facing severe poverty and struggling with profound depression, her inability to cope with compounding tragedies led to her family's fracture.

Nacho is Leo's estranged uncle. Following the dissolution of Leo's immediate family, Nacho and his wife took the young boy in, though the environment they provided left Leo feeling like an unwanted burden rather than a loved family member.

Izzy is Leo's aunt, who, along with her husband Nacho, raised Leo after his parents were no longer in the picture. She eventually sends a dismissive card for Leo's wedding, highlighting the cold and distant nature of their relationship.

Nathaniel is a man found seeking shelter in the ruined remains of the Torres family home in Argyle. He shares a quiet, intense moment sheltering from a tornado with the estranged couple.