The Captains Daughter by Jeff and Jacqi Lovell

Macey discovers her dad has taken a job across the country and must leave her home and friends. In order to soften the news, her parents take her on a vacation to Walt Disney World. At Blizzard Beach, she and a boy named Luke zoom down a water slide but pop up in water hundreds of miles away in the freezing Atlantic Ocean and a long way from shore. They are able to use a pendant that magically takes them to the shore of a secluded island. There a mysterious friend introduces them to the legend of the Ghost of White Island. The teens hear the courageous story of Martha Herring, forced into marriage with a brutal pirate, and abandoned on the miserable rock. The pirate goes back to sea, leaving Martha to guard his treasure. This is a recounting of her adventures and the challenges she and the people in her life endured. It is also the story of how the bonds of strong friendships can impact our lives.