Kate, a shark expert traumatized by a close encounter with a great white shark, has withdrawn from ocean diving and now gives educational tours about the sea. Her idyllic life is disrupted when her ex-boyfriend Jeff shows up with a lucrative proposition: to take a thrill-seeking millionaire, Brady, and his son on a dangerous shark-watching expedition. Though hesitant at first, financial pressures and Jeff’s insistence compel Kate to reluctantly take up the offer, leaving the safety of coastal waters to venture back into the perilous open sea, known for its aggressive shark population.

As Kate leads the expedition, tension escalates between her, Jeff, and Brady, with rising stakes both emotionally and physically. The initial excitement of observing sharks quickly turns into a desperate struggle for survival as the creatures become increasingly aggressive. The team's lack of experience in handling such danger becomes apparent, pushing each character to their limits. The voyage tests Kate’s leadership, their personal relationships, and their resilience against nature's deadliest predators. As conditions worsen and trust begins to fracture among the group, they must find a way to navigate through the treacherous waters without falling victim to the very sharks they set out to observe.