A Lesson in Darkness: Primarchs: The Horus Heresy

Piamen is a tranquil world in the far reaches of the galaxy. Since throwing off the yoke of alien invaders, they have remained free and peaceful...until the coming of the Imperium. When they refuse to join mankind's star-spanning empire, a force of Legiones Astartes is despatched to bring the planet to compliance. And when the Night Lords come, darkness falls. Piamen will never be the same....