When Henry Harper and his little sister Lucy move into a creaky old house, they expect unpacking, not mystery. But in the shadowed backyard stands an ancient oak carved with a compass, a star, and an hourglass-marks that shouldn't be there and a secret that definitely shouldn't open. One brave touch is all it takes for the tree to awaken, and suddenly the siblings are ripped out of their quiet new life and thrown into the open Atlantic... centuries in the past.
They land on the deck of a real pirate ship-the Whydah Gally-where salt spray stings, cannons wait, and every mistake can cost a life. Worse, the captain isn't a storybook villain. He's Captain Samuel "Black Sam" Bellamy: sharp-eyed, fearless, and dangerously fair. As Henry and Lucy struggle to blend in, they're pulled into the ship's tense routines, uneasy codes, and the growing shadow of a storm history says no one can outrun.
With time tightening like a noose and the sea turning treacherous, Henry and Lucy must decide what the compass tree brought them here to do. Was it to witness a legend... or to change one?