Sammy Keyes and the Skeleton Man by Wendelin Van Draanen
This Halloween is more than just tricks and treats--it's deadly serious.
It was supposed to be a simple ding-dong ditch. A dare to give them bragging rights. But as Sammy and her friends sneak up to the spookiest house in town, they get scared witless by a skeleton, and then witness something frightening enough to make even Sammy scream.
Things have taken a scary turn at school, too, with horrible Heather spreading embarrassing rumors about Sammy. Sammy devises a plan to expose her, but it's going to take a deceptive disguise, some good friends, and a lot of guts to pull it off...