The third of seven brand new 39 Clues stories, leading up to one explosive reveal. The Vespers are looking for new recruits and have targeted a few candidates: the Cahill children on the hunt for The 39 Clues. Uncover the Vespers' chilling plan to monitor the Kabras, the Holts, Jonah, and the Starlings, and learn who they picked as the most promising Vesper . . . and future Cahill traitor.