Leighton is an imaginative eight-year-old who makes forts and goes on pretend adventures. In this picture book, Leighton is taking a bubble bath and begins to think about the time she won a prize at the bottom of a cereal box. Leighton uses her imagination to pretend she swims in cereal to the bottom of the cereal box, which is the bottom of her bathtub. She is careful as she looks for her treasure because she imagines an evil octopus is following her and trying to trick her into losing her prize. Luckily, she is helped along the adventure by her toys, a doll, and a rubber ducky. Leighton finds the prize, but it is not the type of prize that you would think she would find.