With the Space Marine Legions falling upon one another in open battle, the most flawed of the mighty primarchs began to pursue their own agendas, seeking out whatever destinies they imagined for themselves under Horus's new order. Fulgrim, the Phoenician lord of the Emperor's Children, had always striven to outshine his brothers - but even he could never have guessed the depths of betrayal to which he would eventually sink in pursuit of greater power...

The Horus Heresy continues in this omnibus, with the fall of the III Legion to Chaos. The novels Fulgrim and Angel Exterminatus serve as a chronicle of Fulgrim's corruption, while The Crimson Fist, The Reflection Crack'd and many other tales from the New York Times bestselling series reveal the true extent of his damnation.