Caroline is really excited that her best friend has just gotten a guinea pig. Caroline and Millie want Navy and Butterscotch to meet and become best friends, too. Despite their hopes, though, it starts to look as though things might not work out. Meanwhile, Caroline's neighbor begins collecting zipper pulls. They're all that Stanley can talk about Since Mom watches him a lot, Caroline discovers her summer days are suddenly filled with an alien invasion. Written in journal style with illustrations based on how the author drew as a child, the Caroline's Cavy series presents young readers with a pair of believable and fun-loving new friends.