When Meg and Peg, her younger sister, explore an old watchtower on a tiny island off the coast of Spain, they meet Tony, a lizard who can grant wishes. By mistake, Meg wishes the three back to the eighteenth century. When they meet and become friends with José and Juan, two boys from the island, the girls realize there is something wrong. What are the boys terrified of? Is it true that there could be a pirate attack at any minute? While they help the islanders to prepare against the invasion, Meg and Peg stumble over a treasure trove and hear some scary and exciting stories about the history of the island, as well as learning more about Tony and his strange powers.