Bertie Bucket and Sandy Spade are collecting shells to paint on the beach. They're hugely excited to find an Oyster Shell, which they hope will contain a pearl. But they're not the only ones interested in their find - an evil seagull called Bagshot kidnaps Bertie and the Oyster Shell in an wicked attempt to get his claws on the pearl. Can Bertie's friend, Shelby Seagull, save the day and rescue him before he drowns at sea? Find out in Bertie Bucket and the Precious Pearl, the third book from the Whistle-on-Sea series.