Defend the Clues: Fourteen-year-old Amy Cahill and her younger brother Dan, thought they could return to their regular lives when they found the 39 Clues that safeguard their family's great power but they were wrong. Powerful enemies the Vespers have been waiting in the shadows and they'll stop at nothing to grab the Clues. Four powerhouse authors unite to expose the 500-year-old secret struggle between the Cahill's and the Vespers. The Vespers are rising and the world is in jeopardy.