Arthur gets annoyed with D.W. when she blames accidents she causes on her imaginary friend, Nadine. While on a trip to the amusement park after hearing about a new ride, Arthur and Buster fear D.W. will embarrass them with Nadine. Arthur is the first to borrow a new book from the library, but he accidentally drops it on his way home. Arthur recruits Binky to help him find the book by interrogating his friends, but it turns out Binky found it after Arthur dropped it.