Ready, Steady, Swim!, Hardcover by Courtenay, Lucy; Dempsey, Sheena (ILT), ISBN 1419745220, ISBN-13 9781419745225, Brand New, Free shipping in the US

At Lady Sealia Foam's Mermaid School, Marnie and her classmates participate in an athletic competition, but when the crown, awarded to the winner, goes missing, Marnie swims to the rescue.