The Black Circle by Patrick Carman
INCOMING! Amy and Dan have been found UNHARMED! But perhaps not for long - the ruthless Irina Spasky is right on their tail. And WHAT are those crazy kids doing poking their noses into Lucian secrets?!? Are they TRYING to get themselves killed? The 39 Clues Book 5 takes Dan and Amy on their most dangerous quest yet, one that brings them face to face with the only force capable of scaring the vicious Lucians: the Madrigals