YACHT SINKS! JEWELLERY LOST! MASSIVE REWARD OFFERED! Ever since the shipwreck, California's golden coast has been filled with treasure hunters. Each one is after the same thing: the lost diamond necklace. But none are more determined than Cassie Stein. Her dad's beloved aquarium is falling apart, and they need money - fast! While racing to find the treasure before her rival, TJ, Cassie finds something remarkable. A fish, unlike any she has ever seen, that can understand her every word. His name is Blue, and his life is in grave danger. To save her new friend, Cassie must do the unthinkable - accept TJ's help. But with the diamond necklace still up for grabs, can she really trust him?