R.L. Stine 
Dangerous Girls 

From the New York Times-bestselling author of Goosebumps and Fear Street, "a fast and breezy vampire tale punctuated with a few nasty shocks" (Publishers Weekly).Destiny Weller and her twin sister, Livvy, return from their summer vacation with an overpowering thirst-an inhuman desire to drink blood.Have they turned into vampires?How will they keep their horrifying secret from their family and friends?And can they find a way to become human again . . . before it’s too late?"Stine’s many fans will be satisfied." -School Library Journal