The third installment of this Edgar Award-mominated series (for Wreck at Ada's Reef) is another engrossing two-pronged adventure—an island mystery and the long-simmering control over Swallowtail Island.
Following the Swallowtales writers’ conference, there are two visitors to the island. Chase Kannen, a dashing, 30ish explorer/adventurer arrives on a huge expedition yacht in search of a bronze statue of Cassandra (of Greek mythology) lost off the deck of a cargo ship in a storm on the lake in the 60's. He has a film crew with him, making a documentary about the search. They find the statue, but shortly thereafter, while it is displayed on the deck of the yacht, it disappears. If it's not found, Kannen will be able to collect the insurance money, which is in the millions.
Meanwhile, Lark and Pip's Aunt Abigail (their mom's estranged sister), arrives by ferry. The sisters haven't seen their aunt since they were 5 and 3, and are not sure why she has decided to come now. Of course, it turns out Aunt Abigail has heard about the deed of land on Swallowtail that might Lark and Pip very rich. Aunt Abigail has a scheme to get the girls to sell their rights to the land . . . with her help, and "for a small percentage."