The peaceful kingdom of Baristan has an evil ruler named El-Carim. He plans to capture his rival, Sindbad, who will soon return from sea in order to marry Princess Jana. The Princess convinces the magician Galgo to turn her into a small bird, so that she may fly off to warn Sinbad of the trap set against him. She flies off just as Galgo is discovered by the guards, who take him to El-Carim. As Sindbad and his crew sail towards Baristan, the Princess-Firebird descends and lands on the ship. But before she can deliver the message, El-Carim transforms the guards into giant human falcons, to drop rocks onto Sindbad's ship sinking it. However, Sindbad and some of his crew have survived, and they carefully make their way to shore. Galgo makes his arm stretch out to an enormous length, long enough to grab El-Carim's magic ring, but the evil king wakes up in time to burn Galgo's hand. Sindbad manages to get arrested, and soon appears before the dictator as a petty thief. El-Carim is not fooled, and knows that the man standing before him is the Princess' suitor, and orders him executed. However, Sindbad breaks free of his ropes and challenges the ruler. Sindbad stabs the King in the heart with a sword, but as El-Carim has no heart, and cannot be killed. El-Carim plans to put Sindbad to death the next day in the public arena. Soon, the poor prisoner is tossed into the arena, where he must do battle with "The Thing," a fearsome giant invisible monster. Fortunately, the Thing knocks over a torch, starting a fire in the arena which incites a mass exodus, allowing Sindbad to escape...