Bobby is a 37-year-old salvage diver living in New Orleans in 1980. A former physics prodigy and racecar driver, he abandoned his scientific pursuits and now lives a transient existence. He avoids his past, specifically the scientific legacy of his physicist father and the deep grief he carries for his sister. His routine is disrupted when he investigates a sunken jet and discovers a missing passenger, prompting federal agents to question him.

Alicia is Bobby's younger sister and a mathematical genius. She lives with schizophrenia and frequently converses with an imagined cast of performers in her room. She possesses an exceptional intellect but struggles with severe despair regarding the indifference of the universe. She relies heavily on the thought of her brother for emotional stability while independently exploring complex theories of existence.

The Kid is a recurring hallucination who frequently visits Alicia. He appears as a short man with flippers instead of hands, a physical form resulting from a mid-century morning sickness medication. He acts as a hyper-intelligent conversational partner who relentlessly questions Alicia about her motives, her math, and her views on reality. He attempts to distract her from her darkest thoughts through coarse jokes and unwanted auditions of other imaginary figures.

John is an English intellectual and a friend of Bobby. He faces legal trouble for selling prescription drugs in Tennessee. He enjoys fine wine and delivers lengthy philosophical monologues about human existence. He observes Bobby closely and offers blunt assessments of his friend's emotional state, believing that misery is a choice.

Debussy is a transgender woman and a loyal friend to both Bobby and Alicia. She carries the emotional weight of her family's rejection while maintaining a belief in a higher power. She meets Bobby in local bars to listen to his troubles and provides practical support when he needs someone to handle sensitive correspondence.

Oiler is a salvage diver and Bobby's trusted colleague. A Vietnam War veteran, he speaks plainly and offers direct advice about survival. He encourages Bobby to face his fears directly rather than trying to ignore them.

Granellen is the maternal grandmother of Bobby and Alicia. She lives a simple, faith-guided life in Appalachia. She provides daily care for her ailing relative and offers Bobby an alternative perspective on existence, insisting that people must actively believe in their own capacity to do good.

Kline is a professional private investigator who formerly worked as a fortune teller in a traveling carnival. He evaluates Bobby's complicated situation involving federal agents. He provides practical, business-like guidance on how to evade pursuit and secure false identities.

Miss Vivian is one of Alicia's recurring hallucinations. Unlike the abrasive Thalidomide Kid, she presents herself as a poised and compassionate figure. She engages Alicia in calm discussions about human suffering and the nature of consciousness at birth.

Lou is a dispatcher for the diving company that employs Bobby. He works at the main office and remains entirely indifferent to the unusual circumstances surrounding the unpublicized plane crash.

Royal is Bobby and Alicia's uncle. He experiences declining mental faculties and rests at Granellen's home in Tennessee, requiring her daily support and supervision.

Borman is an old friend of Bobby who lives intentionally in squalor. He resides in a rural, swampy area near Lafayette and appears completely detached from standard reality.

Asher is an acquaintance who meets Bobby in Knoxville. He listens as Bobby explains complex quantum physics theories and discusses the history of the Western family.

Janice works at the Seven Seas bar. She takes messages for Bobby and alerts him to the recurring presence of federal agents who come looking for him.

Webb is a friend of Bobby. They run into each other on the street, where Bobby buys him cigarettes and confesses his paranoia about being followed by unknown agents.

Red is a coworker of Bobby. They drive together to pull a sunken barge from a river, working blindly in zero-visibility water to attach a cable system.

Russell is a coworker at the river salvage site. He asks Bobby to calculate the exact time required to drain and pull the sunken barge from the water.

João is a man Bobby converses with at a bodega in Ibiza. He shares stories of a friend lost in the Spanish Civil War and handles Bobby's incoming mail.

Bianca is a woman at the local bar. She listens to John Sheddan share gossip about Bobby's past, his racing career, and his family history.

Crandall is a ventriloquist's dummy hallucinated by Alicia. He emerges from a trunk and speaks crudely to both Alicia and The Thalidomide Kid.

Jeffrey is a patient at the Stella Maris psychiatric hospital in Wisconsin. He is a friend of Alicia who meets briefly with Bobby when Bobby visits the facility.