Nancy returns from her trip to Mexico ready to show off her tan and her new charm bracelet, but when class starts the kids are more interested in the choosing of the new crossing guards. When Miss Graves selects Polly and Arthur as the new guards, the kids soon discover that both her choices are a nightmare to have helping you cross the road. While Polly insists that every student learns the seven safety tips, Arthur begins charging people to cross at his corner. When Polly is almost hit by an ice-cream truck, Miss Graves learns that Arthur has been charging and forces him to use the money to buy Polly a get well present and when Arthur gets to the crossing the next day, he learns that crossing lights have been installed. Meanwhile Nancy's good luck bracelet goes missing and she tries to find out who has stolen it, only to discover that it was never stolen in the first place, it just got misplaced in her coat.