Trust No One (The 39 Clues: Cahills vs. Vespers, Book 5)

Thirteen-year-old Dan Cahill and his sister, Amy, are thrust into a desperate battle when seven family members are kidnapped by the elusive Vespers. As the siblings work to uncover a hidden traitor within their ranks, they race against time to save their loved ones from imminent danger. With the stakes higher than ever, Amy and Dan must determine who can be trusted in a fight that could tear their family apart.