Aon, a solid core planet made from the priceless and most dense element in the galaxy, caladium, is under silent attack. Plans are made by off-worlders to dissolve the unbreakable core using crude oil obtained from 19th century earth. Once the oil is refined, the byproduct, gasoline, will soften the caladium, allowing it to be collected. It is soon discovered the core is made from living beings created from caladium itself. The off-worlders employ a band of corrupt inhabitants to carry on this work. They find themselves in a constant struggle with a small coalition of Aonians bent on saving their home world. Both factions clash with the indestructible core creatures. With horrendous beasts one step behind and deadly pitfalls ahead, the coalition struggles to finish its journey, hoping to insure their races' survival.