Trot, a Vietnamese American surfer girl, and Cap'n Bill, her cranky one-eyed cat, catch too big a wave and wipe out, sucked down into a magical underwater kingdom where an ancient deep-sea battle rages. The beautiful Sea Siren mermaids are under attack from the Serpent King and his slithery minions--and Trot and her feline become dangerously entangled in this war of tails and fins.