Ghost Princess by Steve Underwood
The second book of the Daughters of the Lost King series begins with Tic and Plover’s return to Port Town, and their happy reunion with good friends Toadie and Doctor Ngondo. Their happiness fizzles when Tic receives a cryptic message from her sister, Ghost, who has been threatened with a forced marriage to Duke Vaneer’s idiotic son, Ralph. With the help of Professor Schmelkopf, and Ghost’s true love Jacob, the panic-stricken princess has gone into hiding in Azarule’s castle, right under the noses of their enemies.
As the plot unfolds and our heroes are sent into battle, Tic and Plover are detoured by a band of pirates—and a mythical beast who unveils secrets about King Phillipe’s disappearance.
Meanwhile, Duke Vaneer and the Midloathians have usurped the Azarulian throne, while in Polaris, Count Plumdom and Amis must use their new alliance to free the Azarulian Kingdom … even if it means war.