From Back Cover:
Average looking Sheila Holland feels like an ugly duckling. Then, while looking for a costume for the Nightmare Clubs Halloween party, she finds a weird mask at a local antique barn. When she puts it on, she changes into a real knockout. Soon she's getting lots of attention - even sexy Ian Montgomery is pursuing her. But when good looking kids start dying, Sheila begins to suspect the horrible truth... The Mask has a guardian called Shadowman. Each time Sheila wears it, he grows stronger. Unless she can resist his seductive magic, she will become a prisoner of his murderous evil forever.