International media sensation Natalie Collins is an eighteen-year-old Olympic swimmer, who has dedicated her whole life to her career. But when her best friend and relay teammate, Annie, is diagnosed with terminal cancer, Natalie's world spirals out of control. A public meltdown exposes her addiction, leading her to The Dunes, an unconventional rehab in the California desert. At The Dunes, Natalie meets a diverse group of individuals, each with their own struggles and stories.

Mitch, a young counselor who all the girls' crush on, encourages her to write letters to Annie, helping her process her emotions. Through one-sided letters Natalie relays stories about Dr. Blaine, an enigmatic psychiatrist, and Tillie, a nurturing counselor. Among the residents, Natalie befriends Staci, an aspiring artist and heroin addict, and Fiona, a former beauty queen recovering from human trafficking. She also takes on Missy, the rehab bully and her minions, but finds allies in Gia, a former gangster, and Cassidy, a meth addict who believes she lives in a television.

As Natalie navigates her new environment, she reflects on her life in limbo "on the outside." Her father's remarriage to Mommy New Boobs, her mother's churning of her bank accounts and her toxic relationship with Racer, her ex-boyfriend. Through observing others Natalie learns that everyone has their own battles. Inspired by the resilience of those around her, Natalie begins to see life as a gift and the attempts to rebuild her life and career.

"Treading Water" is a story of struggle, redemption, and the power of human connection. From the depths of addiction to the surface of hope.