Our favorite worrier is back, and Stuart is about to start third grade. As he makes his way to the first day of school, wearing the worst outfit ever, what could a first-rate worrier do but worry? Stuart worries about getting stuck in the boys' bathroom, about not having anything to show for show-and-tell, but most of all, about not making any friends. With his cape, though, Stuart is bound to have a day full of wacky adventures.