There's a devil in disguise in the next Sweet Valley High book from Francine Pascal, Too Good to be True.
When glamorous, sophisticated Suzanne Devlin visits Sweet Valley from New York City, the Wakefield twins couldn't be more excited. For two weeks, Elizabeth will show Suzanne around town while Jessica will have the time of her life in New York. Suzanne is perfect: beautiful, friend, and not the least bit stuck up.
But when Suzanne accuses their teacher, Mr. Collins, of trying to seduce her, Elizabeth knows there's more to Suzanne than meets the eye. Can she stop Suzanne before it's too late?