"It is 1884, and Molly and Cassandra Pepper, Emmett Lee, and Emmett's long-lost father are sailing back to New York following their death-defying adventure in Antarctica. Having discovered a subterranean world at the South Pole while saving the world from certain doom once again, surely their accomplishments will finally earn them the recognition they deserve. Unless, of course . . . well, you know by now. And so do the Peppers and Lees. They're...

The Aldens are recruited by the secret Reddimus Society to return lost artifacts and treasures, but encounter enemies of Reddimus during a private train trip to New Mexico.