Pip and her friends are excited to go trick-or-treating, but her grandmas could spoil Halloween! Grandma Sal loves to dress up and insists on playing tricks. Grandma Nan, on the other hand, refuses to wear a costume and insists on good manners. While the grandmas argue, Pip and her friends decide to play their own trick -- and run straight into some scary surprises that make this a Halloween they will never forget.

First introduced in The Grandma Mix-Up, Pip and her grandmas return for a fourth book to add suspense and excitement to one of beginning readers' favorite holidays -- Halloween.