5 parts Complete MatureSome planets look ordinary because they are ordinary. Reast looks ordinary but isn't, and the Culture thinks it knows why. Someone or something is manipulating the planet and its population, and doing so in ways that look awfully like a Mind is involved.
For Special Circumstances agents Bren and Lesk-Torlip, the mission is clear - find out what is going on, and probably die doing so. For the Minds, things are less clear. The reputation and future of the Culture is at stake, but unless they can work out what their opponent is trying to achieve, even the smallest act could lead to disaster.