Sloan Masterson, former WWII bomber pilot, is the captain of a C-119 flying boxcar, the Rocinante, which he co-owns with his female co-pilot, Morgan Reilly. They land their cargo plane in Cuba during the early hours of January 1, 1959. Before they can unload their shipment of medical supplies, they are informed that the ruthless and corrupt President Batista has abruptly fled the country, providing Fidel Castro with the opportunity to seize power.

Sloan makes an excursion into Havana to seek his ex-girlfriend, Carilla Sanchez, and to deliver a message to Brett Lane from the man's mob-connected brother, Andrew. Inside the city, he is confronted with the ugly reality that the streets have been overrun by uncontrolled mobs of political dissidents. Even more alarming, the casinos and hotels owned by the American gangster-profiteers are being wrecked and looted. When he discovers that Carilla and Brett have gone into hiding, Sloan begins a search for the Americans despite great personal risk.

Morgan, without Sloan's input, is persuaded by a group of prominent Cubans to undertake a dangerous and unpredictable covert operation. Fearing the influence of Castro's Marxist dictatorship, they insist that she fly their sons and daughters to America aboard the Rocinante.

Domingo Segunda is reputedly the mosty powerful crime boss in Cuba. With President Batista gone, Segunda realizes that his criminal activity and strong ties to the former president will never by forgiven by the new communist regime. In desperation, he decided to steal the Rocinante and use it for his own escape plans. But Segunda is unaware that Ricardo Cortadellos, his personal lawyer and business associate, has his own hidden agenda. As events unfold, Ricardo imprisons Carilla and Brett in Segunda's walled compound, the Pearl Palace. He then conscripts Sloan to locate a fortune in diamonds, stolen from the mob, as the ransom required for the release of the Americans and safe passage home.

Sloan and Morgan, each operating separately, must allude the sinister characters stalking their every move and complete their respective missions against increasingly desperate odds. At stake is their human cargo's only hope of reaching America and freedom.