Richard is a fourteen-year-old boy living in Florida. He is grieving the loss of his biological father to a skateboarding accident. The trauma deeply affects his daily life and fears. He possesses a sarcastic sense of humor and strong observational skills. He has a deep respect for wildlife and takes it upon himself to track down his missing cousin.

Skink is a rugged older man and military veteran who lives off the grid. He wears a flowered plastic shower cap, has an artificial eye, and eats roadkill to survive. Driven by a strong dedication to protecting the environment and endangered animals, he acts as a guardian of the Florida wilderness and becomes a crucial guide for Richard.

Malley is Richard's intelligent and rebellious cousin. She faces the prospect of being sent away to a boarding school in New Hampshire. She acts impulsively to escape her parents' plans. Her resourcefulness and quick thinking are tested when her plan to run away places her in immediate danger.

Terwin Crossley is an older man with a criminal history who meets teenage Malley online. He convinces her to run away from her family rather than attend a boarding school. He is controlling and impulsive. He demonstrates a complete disregard for wildlife and the natural world around him.

Trent is Richard's good-natured stepfather. He works in real estate and has a friendly, casual relationship with Richard. Though he is not the sharpest adult in the room, he cares for his stepson and is easily distracted by his interests, such as his belief in mythological creatures.

Richard's mother is a lawyer who specializes in environmental cases. She is highly protective of her son, especially after the loss of her first husband. She worries constantly when Richard is out on his own, insisting on regular updates and threatening to call the police if he disobeys her limits.

Richard's late father was an engineer who died in a tragic collision with a delivery truck. Though he is no longer living, his memory heavily influences Richard's hobbies, musical tastes, and personal fears. He represents a significant emotional loss for his son.

Uncle Dan is Malley's father. He frequently disciplines his daughter by taking away her cell phone when she disobeys him. He is initially unaware of the danger his daughter is in because he believes her lies about heading to New Hampshire early.

Beth is Malley's best friend. She is aware of Malley's tendency to break the rules and helps cover for her absence. She even assists Richard by impersonating a mother on the phone to help him secure permission to leave town.

Detective Trujillo is the police investigator assigned to Malley's missing person case. He tries to track down the stolen license plate on the car that picked her up and relies on Richard to keep detailed notes whenever Malley manages to call.

Dodge Olney is a local criminal who digs up sea turtle eggs from the beach to sell on the black market. His illegal activities make him the target of a violent stakeout.

Mr. Tile is a highway patrol officer and a loyal friend to Skink. He uses his position in law enforcement to quietly support Skink's off-the-grid lifestyle, providing him with vehicles, covering up his existence to the media, and intervening at strategic moments to help Richard.

Nickel is a stingy, opportunistic river barge captain. When Richard is stranded alone in the rain, Nickel refuses to help the teenager beyond what his small amount of cash covers, forcing Richard to offer up a hidden stash of money to secure passage.

Dime is Nickel's brother and a local fisherman. He is bribed into renting out his vessel to Richard and Malley for a few hours. He eventually runs into trouble with law enforcement after taking a joyride in an abandoned car.