Austin and the Lost Kingdom of Atlantis

Ancient legends tell of an almost forgotten civilization possessing flying fighting machines, vast armies, and a source of limitless free energy called Vril.
In the middle of the twentieth century two rival submarines from warring nations in our world raced to find the lost continent of Atlantis and the source of Vril. One nation aimed to secure world domination, the other sought to preserve world freedom.
Neither submarine was seen again until the present day when one of them is discovered in a secret subterranean dock and caught suddenly in the world's energy-hungry gaze.
In a bid to stop the secrets of Atlantis from destroying mankind in the present day, the sub escapes its secret moorings for a perilous return voyage to Atlantis.
Here in “Austin and the Lost Kingdom of Atlantis” - the sequel to "Austin and the Secret of Karnak House" - school friends Bill Young and Toby Wishman, Bill's heartthrob Lulabell Singer (Lu), and their arch enemy Stu Briggs, find themselves trapped together aboard the Professor's ancient and leaky submarine on a perilous undersea adventure to try to find and rescue the Professor's long-lost son, Rudi, and destroy the deadly secrets of Atlantis once and for all.