The Legacy of Caliban echoes down through the ages, and the secretive mission of the Dark Angels continues: to atone for the sins of their forefathers and capture all of the renegades and heretics known as the Fallen. With the most famous of these Fallen Dark Angels - the elusive Cypher - now firmly in their grasp after his unexpected surrender, the Dark Angels are given fresh hope that they can redeem themselves in the eyes of the Emperor. But what game is Cypher playing? What plans does he have? And can the Dark Angels ever really atone, or will they always remain the Unforgiven?