Approaching the Source continues to follow the battle of good and evil in an ongoing story on the distant and artificial world of Vhast. The people who find themselves in the formerly hidden village of Mousehole begin to find out where their enemy, the Adversaries, are based. Instead of reacting to them, they begin to learn more about them and take them on in their own strongholds. Following on from Intimations of Evil, and the next five books of the series, the Princess, and her wife the mage, the Cat, the priest, the ghazi, and the many others, including free and former slaves, begin to strike out and discover how much they have grown and how they can confound an enemy that has plagued Vhast for thousands of years. Approaching the Source is the seventh and penultimate book of a series where magic is a scientific experiment. Good struggles with evil to control this magic in a world made by an alien race for their own purposes.