Martello tower
Both "The Mystery of the Martello Tower" and "The Legend of the Lost Jewels" follow the adventures of heroine Hazel Frump and her younger brother Ned. Lanthier has said the books’ settings, "Ile du Loup" and "Frontenac", were directly inspired by Wolfe Island, Ontario and nearby Kingston. The Martello tower of the first book's title was based on Cathcart Tower on Cedar Island, just south of Fort Henry National Historic Site.