Rustie knows what he has to do. He’s going to finish what the Great Uniter started and rid the world of the crystals. But first he has to find them. Before the Collector does. Rustie believes Win can lead him to the Keeper of the black crystal. The last of the three great crystals may be useful in the fight against the Collector. Meanwhile, Aiko, Reggie, and the Sage search for the elusive enemy and encounter an unlikely ally. Nothing’s easy for Rustie and his friends. There’s a traitor in their midst. A rogue Keeper leaves a fiery mess wherever he goes. And skeptical Keepers don’t want to give up their crystals. Worse, Rustie learns that the hardest part of his mission is how it ends. He knows what he has to do. But can he do it