Die Höhlenwelt Saga: Der Leuchtende Kristall

Starship pilot Eric "Speedy" MacDoughan traces his lost love, mysterious Maomi, to the barren planet 2S-126 in the Taurus 5 system, to discover that a network of caves leads to a gigantic cave world far beneath the crust. Down there, flying dragons and humanoid peoples live under the despotic rule of an alien reptile race called Drakken. Eric meets the artificial being Cal, who sends him to the cave world to retrieve a powerful energy crystal. And find Maomi, of course.