The film opens with a narration by Daria Nicolodi as a mother tells a bedtime story from a vast, ancient book. In Basra, the evil vizier Jaffar has clouded the caliph’s mind and imprisoned his daughter, Princess Alina, hoping to force a marriage to seize power. Jaffar has scattered four of Basra’s five sacred gems to dangerous corners where they are guarded by protective magic.
Sinbad and his crew arrive at the caliph’s palace, only to be seized by hypnotized soldiers. [Jaffar] sentences Sinbad’s crew to the torture chamber while the mighty Sinbad is doomed to a pit of snakes. He escapes by tying the snakes into a rope and using it to pull his companions free. As they flee Basra, Jaffar calls upon dark powers that conjure an evil cloud over the ship and awaken the Legions of Darkness—the undead warriors. Together with his friends, Sinbad defeats the undead and their fearsome leader.
Sinbad then seeks aid from a wise Oracle on a mysterious island, who reveals the location of the four sacred gems of Basra. He sails to a new island, finds the first gem, and vanquishes a towering rock monster to claim it. Soukra, a sorceress allied with Jaffar, joins the plot and helps sharpen the plan to seize the remaining power. The second gem lies on the island of the Amazons, where the Amazons hypnotize Sinbad’s crew and their leader, Queen Farida, takes Sinbad captive. The Bald Cook and Poochie the dwarf aid in the rescue, and Sinbad retrieves the second gem—the Queen’s necklace.
The voyage then leads to the Isle of the Dead, where Ghost Knights rise from the graves to fulfill an ancient destiny. Sinbad confronts the Ghost King while his companions fend off the spectral knights. Jaffar intensifies the danger by breathing life into the Ghost King with dark magic, weakening Sinbad, but the sailor resists and destroys the Ghost King with his own sword, claiming the third sacred gem.
On the Isle, Sinbad meets Kyra and her father, Nadir, two survivors who arrived there by a flying balloon. With their help, Sinbad teams up to rid the island of its monsters. They encounter a gnawing horde of ghouls, and Kyra is captured. Sinbad rescues her, but must face a terrible monster known as the Lord of Darkness, a creature that fires energy bolts from its wrists and guards the last gem of Basra. Sinbad defeats this evil force with the aid of the gathered gems and claims the final gem, then escapes the island in a balloon with Nadir.
Reunited with his companions, Sinbad and his crew march to confront Jaffar. Soldiers clash as Sinbad battles the vizier, who conjures an exact clone of Sinbad to duel him. The real Sinbad prevails, Jaffar is captured, and Princess Alina is freed. With the four sacred gems restored, peace returns to Basra, and the tale ends as the mother folds the book, the room filling with a soft, hopeful light.
