The 39 Clues Cahills v/s Vespers #2 A King's Ransom

Amy and Dan Cahill have been kidnapped by a sinister group known as the Vespers. They have a ransom demand: If the Cahills deliver the impossible, they might just get Dan and Amy back. But Amy and Dan have just days to track down the Vespers' most precious holding and rescue their friends. The clock is ticking. The ransom is growing. The Cahills have never faced such a deadly challenge.
Pg Nos -190