Irene is a recently widowed Midwestern magazine editor. She discovers her husband maintained a secret life, complete with a mistress and a second family, in the Caribbean. Rather than retreating, she methodically investigates the financial discrepancies of her marriage and plans a temporary move to St. John to uncover the truth.

Ayers is a charter boat first mate and server who deeply grieves the loss of her best friend. She acts as a surrogate aunt to Rosie's daughter, Maia. Finding Rosie's hidden journals presents her with a confusing alternate view of her friend's life and the secrets Rosie kept.

Huck is a pragmatic charter boat captain on St. John who acts as the primary guardian for his 12-year-old granddaughter. Following the sudden death of his stepdaughter, Rosie, he prioritizes Maia's safety while trying to understand the illegal activities connected to Rosie's lover.

Baker is Irene and Russ's older son. He lives in Texas and focuses on co-parenting his young son, Floyd, following his separation from his wife. Seeking a fresh start from his failed marriage, he plans an exploratory trip to the Caribbean to pursue his attraction to Ayers.

Cash is Irene and Russ's younger son, who recently lost his outdoor supply business in Colorado. Feeling aimless, he decides to relocate to his late father's villa on St. John after securing a job as a first mate on a local charter boat.

Rosie is Russ's deceased mistress and Maia's mother. Her perspective is presented entirely through past journal entries discovered by Ayers. These entries detail the origins of her romance with a married man and her growing unease regarding his financial secrecy.

Russ is the deceased patriarch whose helicopter crash sets the story in motion. He maintained a public life as a devoted Midwestern husband while secretly funding a second family in the Virgin Islands through his work at an offshore hedge fund.

Maia is an intelligent, resilient 12-year-old girl mourning the sudden death of her mother. Raised on St. John, she possesses a deep knowledge of the local environment and relies on her grandfather, Huck, and her godmother, Ayers, for support.

Todd owns the Ascension hedge fund and employs Russ. Operating largely off-page, he uses his significant wealth and offshore banking connections to run illicit financial operations, threatening those who might expose him.

Mick is the charismatic manager of the popular Beach Bar on St. John. He has a complicated, off-and-on relationship with Ayers, marked by his past infidelity and his persistent, sometimes public, efforts to win back her trust.

Agent Vasco is an FBI investigator looking into the financial crimes associated with the Ascension hedge fund and the helicopter crash that killed Russ and Rosie. She coordinates the federal response on the island.

Ed is the Steele family attorney in Iowa. He assists Irene in untangling the unexpected financial updates to Russ's will and identifying the offshore origins of their home's purchase.

Tilda is a server at La Tapa who comes from a wealthy family. She plans to start an eco-tourism business and strikes up a connection with Cash Steele.

Anna is Baker's estranged wife. She is planning a move to Cleveland with her new partner, Louisa, prompting Baker to reevaluate his own living situation.

Floyd is Baker and Anna's four-year-old son. He accompanies his father on the exploratory trip to St. John and quickly adapts to the island environment.

Paulette manages the Steele family's St. John villa alongside her husband, Douglas. She abruptly flees the island just ahead of an FBI raid.

Douglas is a real estate agent and property manager who handles the St. John villa. He leaves his office empty to evade federal authorities.

Mavis is the editor-in-chief of the magazine where Irene works. She receives Irene's resignation when Irene decides to leave Iowa and seek answers.

LeeAnn is Huck's deceased wife and Rosie's mother. Through diary entries, she is shown reading Rosie's private thoughts and demanding that she end her involvement with a married man.