The story begins around 150 years ago, in an English town named Wall. Wall is built beside a wall that is a portal to a magical kingdom named Stormhold. After a man named Dunstan Thorne (Nathaniel Parker as the elder) crosses the wall, he meets and makes love to a woman, Una (Kate Magowan), who is the slave of the witch Ditchwater Sal (Melanie Hill). Nine months later, Una sends him a baby in a basket—their infant son, Tristan.

Eighteen years later, the King of Stormhold (Peter O'Toole) is dying, and his seven sons, four alive (Septimus, Primus, Tertius, and Secundus) and three already dead and looking on as ghosts (Quartus, Quintus, and Sextus) fight for who will be the next king. Secundus appears late, and the king tricks him into being pushed off a balcony and down a cliff by Septimus (Mark Strong). Secundus (Rupert Everett) then appears along the other three dead brothers, his face smashed in from the impact of the ground. The King hurls a ruby into the sky, saying that whichever son retrieves it will be king. The ruby knocks a star out of the sky, which the grown Tristan Thorne (Charlie Cox) sees. Tristan promises to retrieve the star for the beautiful yet conventional Victoria (Sienna Miller) to prove his love for her. However, at the same time, three witch sisters see the falling star, and one, Lamia (Michelle Pfeiffer), leaves to capture it so, by devouring its heart, she and her sisters will be restored to beauty and power.