Four children, Kiri, Jed, and twins Emma and Ethan, discover an ‘elastic’ island that can send them pinging across the ocean to a variety of tropical island destinations. Their last destination spelt trouble, so this time the children are determined to have a relaxed and safe time when they visit Port Mugaloo on MugaMuga Island. But Ethan falls into a pond and becomes invisible, and the only one who can help them is King Shiny. But King Shiny has gone missing looking for the long-lost royal treasure, so they enlist the help of Mrs Quokka and travel across the desert on a seven-humped camel into very dangerous territory to find him. But have the children made a mistake in trusting Mrs Quokka? They soon learn that quokkas might be famous for their ‘quokka logic’ but mostly it doesn’t make any sense.