A simple school lesson turns into a high stakes underwater treasure hunt. While the third grade mermaids at Trident Academy are studying the art of storytelling, they uncover a fascinating legend about a pirate shipwreck hidden somewhere within their very own city. The snooty and determined Pearl immediately decides she is going to find the lost gold, no matter the cost. There is just one major problem standing in her way. According to the ancient stories, the legendary pirate loot is heavily guarded by a spooky ghost. Shelly, Echo, Kiki, and the rest of the class must navigate dark waters, decipher old clues, and face their fears of the supernatural. This exciting chapter book brings mystery and adventure to the ocean floor. Young readers will be swept up in the thrill of the chase as the mermaids work to uncover the truth behind the ghost and the glittering pirate treasure.