Not one of the merkids in Shelly Siren's third grade class can believe the shell-shattering news: Shelly is a princess! A real princess! It's been a deep, dark secret in Trident City, but now everyone knows--and Shelly doesn't know how to act. Should she start wearing a glittery crown? Or move to a grand undersea palace? Will her friends have to call her Princess Shelly? She knows it's an exciting turn of events, but Shelly's not sure she can truly fit the royal part. Can she find a way to be a princess and stay herself?