D.W. is scared of the upcoming fire drill in her preschool, so her family names her a fire warden and runs fire drills in their house to ease her fears. During the fire drill, D.W. is able to calm her friends down and lead them outside safely. D.W. wants to prove to the Tibble twins that she can do something they cannot, so she pretends to read them a book, while instead making up a story about a D.W. lookalike named "B.W." Arthur thinks that the Tibbles will find out about D.W.'s trick, while D.W. is glad that she could be better than them for the day. The Tibbles ask to borrow the book, and when their grandmother reads it to them, they learn that it is instead about Leonardo da Vinci, but think it is a "magic book" that changes whenever it is read.