On a sun-drenched island, the former castaways run a thriving vacation retreat called The Castaways, a tropical escape born from the events of the previous film, The Castaways on Gilligan's Island. Thurston Howell III handles mainland business, while his son, Thurston Howell IV, runs the hotel operations from the island paradise.
Their peaceful routine is upended when a plane carrying the Harlem Globetrotters suffers engine trouble over the Pacific and must make an emergency landing on the island. News of the crash flashes across Thurston Howell III's private TV, and soon Gilligan and Skipper discover the stranded guests and welcome them to The Castaways. The Globetrotters, a cheerful traveling basketball troupe, are warmly received, but a friendly game reveals the locals’ confidence in their own abilities as they are soundly defeated by the visitors.
Meanwhile, a ruthless corporate raider named J.J. Pierson eyes Gilligan’s Island as a prize to seize, hoping to sign over ownership to himself by exploiting a powerful ore known as supremium. Pierson’s scheming culminates in a plan to force a deal: the island will be won or lost in a high-stakes basketball match between the Globetrotters and Pierson’s team, the New Invincibles, a squad of robot players. The winner takes the island, and Pierson’s clock is ticking.
The challenge attracts attention from all corners, with notable sportscasters Chick Hearn and Stu Nahan lending their voices to the climactic broadcast as the game approaches. The Globetrotters find themselves stumped by the robotic lineup, and the Professor Professor watches anxiously, unsure how to counter an opponent that seems unbeatable. It isn’t until Gilligan speaks up—remarking that the Globetrotters haven’t used any tricks—that a halftime pep talk from the Professor sparks a new strategy for the team.
With renewed spirit, the Globetrotters begin to chip away at the robots’ lead. They score points, excitement grows, and the pressure tightens as two of the Invincibles are fouled out, forcing a scramble for replacements. Gilligan and the Skipper are called in as substitutes, bringing the toughness and improvisation the island has always prided itself on. In a dramatic finish, Gilligan—fired up by teamwork and a touch of luck—lands the winning shot just as the clock runs out.
Pierson’s smile fades as the true stakes come to light: while everyone has been distracted by the game, he ordered the supremium removed from the mine and loaded onto his boat. The Professor warns that supremium is incredibly unstable outside its natural environment, and Pierson realizes his mistake too late as the element explodes, sinking his yacht and leaving him penniless.
As the celebration begins, the elder Howell returns from his business trip and publicly commends the Harlem Globetrotters for their courage and the castaways for their teamwork. The island’s fate is secured not just by a victory on the court, but by the community’s resilience and the younger Howell’s capable leadership, proving that cooperation and ingenuity can outplay even the shrewdest adversaries.
