The Mute of Pendywick Place And the Ghost of Robin Hood's Bay — Alydia Rackham

It is too late to retrieve the code. Victoria and Basil must instead recreate it, and get it to the queen. To do that, they must travel to the remote Yorkshire seaside, along with Basil's sister and her husband, and their friend Fred Brody, to a vast, empty house of Professor Winchester's. But as they dig through Victoria's old reference books, a phantom begins to stalk them through the hollow corridors and musty smugglers' tunnels. And it may lead the Pendywick Pair to a watery -- or fiery -- clash with the very enemies that mean to destroy them.