Sindbad goes to Galgo and finally convinces the magician to reveal El Kerim's secret: the evil ruler had his vulnerable heart removed, and it is now kept safe in a distant bell tower, guarded by supernatural forces. In the meantime El Kerim insists that the Princess marry him, but when she finally refuses, he orders her to be executed with Sindbad when he is recaptured. Sindbad and his men must traverse a swamp of horror in order to reach the tower containing the evil heart.