In the idyllic Caribbean territory overseen by Xavier Quinn, a once peaceful atmosphere is shattered by the sudden death of Donald Pater, a wealthy resort hotel owner. Initially, the blame falls on Maubee, a small-time criminal and trusted friend of Quinn, though the chief of police is skeptical, grappling with his own marital woes and struggling relationship with his young son due to his demanding job.
As Maubee skillfully evades the law, Quinn becomes engrossed in the investigation, especially after a crucial witness reveals that Maubee had a rare $10,000 bill in his possession. This leads him to seek out Ubu Pearl, the well-respected witch of the island and the aunt of Maubee's girlfriend, Isola.
Amid rising tensions, Quinn faces challenges from Governor Chalk, whose incompetence further complicates matters. An unexpected twist arrives with the appearance of Fred Miller, a charming American who claims to represent Pater's company. He shares a harrowing detail: Pater was discovered decapitated in a hot tub, a victim of a venomous snake bite prior to his head's severance. The urgency of the situation drives Quinn to defy orders by insisting on an autopsy, uncovering shocking truths.
The investigation intensifies with the arrest of Jose Patina, who seems to be a regular tourist but is actually probing for information about Maubee. After being released on bail, he meets a grim fate at the hands of Miller, who later confronts Ubu Pearl, demanding to know the whereabouts of Maubee. When she refuses to cooperate, tragedy strikes as her home is set ablaze, leaving her trapped inside.
Quinn's probing leads him into a complex web of deception, revealing that Pater had connections to the President of the United States. Pater had brought a stash of $10,000 bills to the island to facilitate a covert operation aimed at funding an anti-Communist revolution in Latin America, circumventing Congress's authority. This illicit plan, carried out through the CIA, escalated the stakes when Pater's murder threatened to expose the operation, prompting Miller’s desperate mission to recover the money.
As Quinn's relentless search leads him to nostalgic childhood moments with Maubee, the truth begins to unfurl. Maubee discloses disturbing facts about Pater's past, particularly regarding Isola, who had been a young maid working at the hotel and became pregnant after an encounter with Pater. When Ubu Pearl sought financial assistance for the child, Pater callously fired Isola, igniting a desire for revenge. Ubu Pearl, in her hurt and anger, orchestrated a plan that led to Pater’s death, with Maubee arriving just after it occurred, seizing the opportunity to take the money left behind.
In a dramatic climax, just as Maubee and Quinn celebrate their risky gain, Miller intercepts them, holding them at gunpoint. In a move characterized by quick thinking, Maubee relinquishes the money, allowing Miller to escape in a helicopter. Enraged by the betrayal, Maubee clings to the chopper as it departs over the ocean, leading to a heart-wrenching confrontation as Miller’s gunfire claims Maubee's life. Quinn, left powerless, watches the tragic outcome unfold as his friend’s body sinks beneath the waves.
Upon returning home, Quinn confronts the agony of loss and strives to reconcile with his grieving wife. As he walks with his son on the beach, the camera captures a poignant moment: a trail of footprints emerges from the ocean, culminating at a rock bearing a $10,000 bill—a stark reminder of the tumultuous events that unfolded from their ill-fated adventure, leaving a lasting mark on Quinn's life.
