The Mysterious Benedict Society and the Riddle of Ages (The Mysterious Benedict Society, Bk. 4)

Some time has passed since the inimitable quartet of Reynie, Sticky, Kate, and Constance have had a mission together. But with the arrival of a new Society member -- and a new threat -- they must reunite to face dilemmas more dangerous than ever before, including the villainous Mr. Curtain and a telepathic enemy tracking their every move, not to mention a dramatically preteen Constance.