Pip Bartlett has a way with the magical creatures at his Aunt Emma's clinic, but an extremely timid unicorn named Regent Maximus is testing even his abilities--particularly since it is Pip's assignment to get Regent ready for the Triple Trident show for magical animals where, to make matters worse, somebody is trying to win by sabotaging the other contestants.

Pip and Tomas visit a seaside showplace filled with magical sea creatures and find themselves surrounded by a menagerie of fantastic specimens before becoming entangled in a mystery involving a naughty sea monster that might not be staying in its tank.