The Cromwell clan live in the real world, except for their grandmother who lives in Halloweentown, a place where monsters go to escape reality. But now the son of the Cromwells' old enemy Kalabar has a plan to use the grandmother's book to turn Halloweentown into a grey dreary version of the real world, while transform the denizens of the real world into monsters. Only Marnie, a fledgling witch, can thwart the evil scheme.

Before he died, Dar's father gave a mysterious amulet to Tal, Dar's younger brother who is now king. Dar, while wandering with his animal companions, chances to meet and rescue a family who seek the help of King Tal against Lord Agon, a sorcerer who has conquered their land. Dar obtains an audience for them with Tal, who rallies his troops to march against Agon in the morning. Alas, the young king is captured by Agon's crimson warriors during the night. It is the amulet -- the Eye of the imprisoned god Braxus -- that Agon really wants. But Dar now carries half of it, and is nowhere to be found. Will he fall into Lord Agon's clutches when he comes to free his brother?

A group of friends head to Las Vegas for a bachelor party.. only things go wrong and a woman is killed. Soon, the bodies are piling up and the friends find themselves turning against one another as the coverup builds.

The movie takes place at Witch University, also known as Witch U.