The secret shipwreck

"Kai, Marina, and their friends decide to use the whirlpool at Mermaids Rock to take a trip to the Red Sea. They find a shipwreck, and Kai is enthralled with the human artifacts that they find there. But Coralie is worried that they'll be discovered and urges the group to return home. Then a group of divers arrives at the shipwreck, and the friends find themselves in a tricky situation. Will they be able to return to Mermaids Rock without being seen by the humans?"--Provided by publisher.