The 7th book of the 39 Clues series, Viper's Nest, written by Peter Lerangis. Cards included and sealed.
The hunt for 39 hidden Clues that lead to an unimaginable power have taken a heavy toll on fourteen-year-old Amy Cahill and her younger brother, Dan. They've just seen a woman die. They're wanted by the Indonesian police. They're trapped on an island with a man who knows too much about the death of their parents. And a tropical storm is rolling in. Just when they think it can't get any worse, it does. Because the Cahills have one more rattling skeleton for Amy and Dan to discover . . . the terrible truth about their family branch.