Risk: Quest for Truth, Book 2

Flying to coordinates unknown, the Wikk kids land the Phoenix on planet Evad and descend into an ancient jungle. Revealed is a highly intelligent civilization, whose inhabitants have now vanished, leaving behind astonishing technology! High stakes lead the Wikk kids on a dizzying ride from the pinnacle of a ziggurat into an endless underwater labyrinth. Dive into adventure, as the twins face a deadly showdown with the evil Ubel! Can they win the struggle to survive the savage snares, with the help of the elusive Brother Sam?