The Mission Hurricane (The 39 Clues: Doublecross, Book 3)

Thirteen-year-old Dan Cahill and his older sister Amy face a looming threat as they race against time to prevent their relative, known as the Outcast, from recreating a devastating disaster inspired by Hurricane Katrina. With clues pointing to a potential target, the siblings must uncover the Outcast’s plans and find a way to stop him before it's too late.