Roxana Aubrey (Camille Rowe) drops out of her university studies to attend a freediving course, where she meets world-record holder Pascal Gauthier (Sofiane Zermani). The two quickly enter an intense, passionate romantic affair, and Pascal begins training Roxana in extreme freediving. As Roxana excels and begins breaking records, her rising fame causes severe envy and resentment in the controlling Pascal. As their connection turns increasingly toxic, manipulative, and fractured by infidelity, Roxana turns to team member Tom (César Domboy) for comfort. Pushed into setting a high-risk "No Limit" record by a jealous Pascal, Roxana embarks on a dangerous deep-sea dive that ends in tragedy.