A British intelligence agent is sent to Jamaica to investigate the mysterious disappearance of a fellow agent, John Strangways, and his secretary. The island, lush and exotic, teeters on the brink of a larger conflict as the space race is in full swing and a rocket launch from Cape Canaveral is imminent. The missing agents had been monitoring a powerful radio jamming signal emanating from Jamaica, capable of disrupting rocket launches, which leads the agent to suspect foul play linked to these disturbances. During his investigation, he allies with the local CIA agent and together they comb the island for clues.

Their inquiry points towards the reclusive Dr. No, who resides on the technologically advanced Crab Key island, where no locals dare venture, fearing the mythical "dragon" rumored to prowl there. The agent meets a resourceful shell diver, a woman tied to the island's mysteries, providing him with a valuable lead. They team up and decide to confront the dangers of Crab Key, where the mastermind's intentions, as well as the international implications of his scheme, slowly begin to unravel.