Sinbad [Douglas Fairbanks Jr.] regales a group of travelers gathered around a nighttime campfire, his voice rising and falling as he tries to hold their attention. When the party grows weary of his tall stories, Sinbad shifts gears and begins recounting his eighth voyage with a steady, even tone that invites listening and curiosity in equal measure. The tale unfolds with a sense of adventure that blends danger, luck, and a wry sense of humor, drawing the listeners ever deeper into his world.
With his companion Abbu [George Tobias], Sinbad salvages a ship whose crew has fallen ill from poison, a desperate find that uncovers a clue in the form of a map rumored to lead to the legendary treasure of Alexander the Great on the mythical island of Deryabar. As the ship reaches Basra, a powerful local khan seizes it, intending to auction the vessel to the highest bidder. Sinbad, ever quick on his feet, secures a daring deal: he may keep the ship if no one bids. He works to discourage every potential buyer, insinuating that the ship is cursed and bringing a touch of superstition into the proceedings to keep the price down.
Into this tense moment steps Shireen [Maureen O'Hara], a veiled figure from the emir of Daibul's harem, who appears in the auction with her own agenda. When Sinbad places a bid against her, he cannot cover the debt that would accompany the ship, so he steals the auctioneer’s money to secure it. The encounter sets in motion a web of schemes, secrets, and shifting loyalties that will follow the voyage across seas and deserts.
In the emir’s garden that same night, Sinbad learns of a mysterious and deadly pursuer named Jamal—a threat who will stop at nothing to seize the treasure. Jamal, though glimpsed only behind a curtain, moves with cold precision and quickly makes a move to kill Sinbad. Sinbad narrowly escapes and, with a crew he bulks up along the way, sets sail again aboard the stolen ship, the rumors of Jamal circulating among the men as a dark legend they all fear but have never seen.
Aboard a new leg of the journey, Sinbad returns to Daibul to visit Shireen and, once more, he is captured. Yet the emir, believing Sinbad to be the prince of Deryabar, treats him as a guest rather than a prisoner. Sinbad uses his charm and cunning to slip free, taking Shireen with him as they press on toward the fabled island. The pursuit intensifies when the emir’s forces recapture them, and the truth about Jamal is revealed: the barber Melik, whom Sinbad and the crew had trusted, is the same dangerous mind behind the plot, having memorized and destroyed the map to Deryabar. An uneasy alliance forms as they press onward toward the treasure together.
Arriving at Deryabar, the group confronts Aga [Alan Napier], the sole survivor in the ruins of Alexander’s palace. With a combination of truth and persuasion, Sinbad convinces Aga that he is his long-lost son, a belief reinforced by a medal Sinbad has carried since childhood. Aga ultimately yields, guiding them to the hidden trove. He also reveals a painful memory: he had entrusted his own son to sailors to shield him from those who would murder for wealth. Sinbad indeed is the rightful prince of Deryabar, and the treasure’s promise seems within reach.
Jamal’s treachery comes to a head when it’s discovered that he engineered the emir’s and the crew’s poisoning in order to claim the riches for himself. The emir forces Jamal to drink the deadly liquid as punishment, while Sinbad seizes the moment to retake control of the voyage. He boards the emir’s ship, frees his crew, and sees the emir slain by a Greek-fire catapult launched from his own vessel—a brutal turn that underscores the peril surrounding the treasure.
Back around the campfire, the listeners who had doubted Sinbad’s truth begin to rethink their skepticism as the tale’s surprises accumulate. He distributes jewels and gold as a final gesture of generosity, and the arrival of Shireen on the ship seals the moment. The travelers set course for Daibul on their return to Deryabar, and Sinbad closes his tale with a moral: true happiness lies beyond material wealth.
