Finley the Fish and his friend, Challenger, think they're just going on a treasure hunt. Even though Grand Pappy Fin has warned them to be on the lookout for dead bodies and monster fish, they decide that it's worth the risk in the quest to see real treasure. With help from the Land Crew, they locate the area where the boat sank, but in order to see it, they have to swim WAY down. What they don't know is that danger lurks in the deep waters! Can they find the treasure without being eaten alive by monster fish? More importantly, can they save their friendship from the grip of jealousy? When their new friend, Chip, is caught by some men on land, their faith is tested in a whole new way.