In December 1958, Major Robert Dapes (Sean Connery), a former British military officer and counter-insurgency expert, arrives in Havana, Cuba, with intentions of working as a mercenary. He has been recruited by General Bello (Martin Balsam) on behalf of the military dictator General Fulgencio Batista. Their goal? To assist the Cuban army in quelling Fidel Castro's rebellion. On the same flight, American businessman Larry Gutman (Jack Weston) is greeted at the airport by the sophisticated and poised Alexandra Pulido (Brooke Adams). As Robert catches a glimpse of her, he believes he recognizes her from a previous romance, but is unable to reach her before her chauffer whisk her away. His military escort, Captain Ramirez (Hector Elizondo), informs him that she is married to a prominent member of one of Cuba's wealthiest families.
Alexandra soon takes Gutman to manage her cigar factory. Meanwhile, her husband Juan Pulido (Chris Sarandon) is entangled in a scandalous affair with factory worker Therese Mederos (Lonette McKee). When Alexandra returns, she witnesses a flirtatious encounter between them and subsequently fires Therese in a demonstration of her authority. Juan, determined to impress Gutman, showcases the vast family business that spans tobacco, sugar, and rum. During a meeting with Don Jose Pulido (Walter Gotell), Juan's father, Gutman learns that while Juan fancies being a playboy, it is Alexandra who runs the factory.
Robert, choosing modest lodgings over a luxurious hotel, meets with General Bello to discuss the military strategy against the rebels. He warns that Castro's forces will be difficult to defeat if the populace supports them. Days later, Robert encounters Alexandra at a military barracks, only to find she rebuffs his attempts at friendship, steadfastly reminding him of her marriage.
Amidst escalating violence in Cuba, rebels attack a high-society gala attended by General Bello, resulting in panic and loss of life. As Robert and Ramirez arrive on the scene, they step into the chaos to aid the wounded. Caught in this conflict is Julio Mederos (Danny De La Paz), an ambitious young rebel who seeks vengeance against Juan. Tensions rise further as Alexandra grows frustrated with Juan during a Christmas party at a nightclub, where her past with Robert comes rushing back.
> "I remember a time when we were both happy..."
While an imminent assassination attempt on Juan is thwarted by Robert, the political landscape in Cuba shifts dramatically. A rigged election results in Rivero Agüero becoming President, chosen by Batista. This ignites further unrest as strikes fill the streets. Alexandra’s moral struggle deepens as she devotes herself to the factory and her family, yet she senses her unhappiness in marriage.
As Julio's desperate actions lead to more bloodshed, Robert discovers Alexandra in danger. A clash with Castro's forces ensues at a strategic location where Robert decides to aid the rebels, breaking free from the government's grip and showing his allegiance to the Cuban people. This decision culminates in a fierce battle, where fire and chaos reign, and lives are lost on both sides.
In a dramatic twist on New Year’s Day, Robert tries to persuade Alexandra to flee Cuba with him, but she feels caught between her obligations and desire. As he turns to leave, tragedy unfolds when Juan is murdered by Julio. Amidst the turmoil of the airport and the mad escape of Batista and his allies, Robert hopes against hope that Alexandra would join him. However, destiny pulls her back to Havana as she must confront her uncertain future alone.
The film concludes with the turmoil in Cuba evident and Fidel Castro arriving as the new leader, leaving audiences to reflect on the personal and political upheavals of the time, as the screen fades to black with the poignant text: Cuba, 1959.
