Marco Polo is a small felt mouse who used to be a Christmas ornament on Anne the librarian's tree. But now he's one of the Book Buddies, toys that can be checked out just like books. Marco Polo may be small, but he's also a brave explorer looking for adventure—if only someone would check him out of the library. Seth is a boy who visits the library with his dad and younger brother. He wishes he could be a little more brave, especially when he goes on his first sleepover. But maybe a small explorer like Marco Polo is just the kind of friend he needs. From Newbery Honor winner Cynthia Lord, here is the second title in a heartwarming series about a group of friendly toys at the library and the children who borrow them.