Title: The hidden kingdom
First published: 1900
Description: Having saved Europe from the Professor's war schemes in *The Seven Sleepers*, Thomas reunites with his friends Étienne and Gaston of the French secret service and discovers that the Professor is at work again — this time with a plan for world domination that will carry them to Outer Mongolia to witness the fulfillment of an ancient prophecy.
LC classification: PR6003.E3 H5 1900z