When Arthur hears his sister singing a catchy tune, he wonders if he could call that jingle his own and enter it in the Crunch Cereal Contest.

Arthur and Francine aren't speaking to each other, but Mr. Ratburn has paired them up for a homework project. They go to the library to do some research, and find themselves locked in after it closes. Can they set aside their differences and work together to find a way out?