The Blood Angel once known as Calistarius is no more. In his stead lingers a remnant of that proud scion of Sanguinius. He is a wraith, a dark tale to chill blood, an inscrutable enigma. He is Mephiston, Lord of Death. As Chief Librarian of the Blood Angels Chapter, his powers are formidable, his legend terrifying. Powerful as he is, Mephiston is sorely tested when he descends with his brothers to Pallevon following a rumour about their slain primarch. But there are secrets on this world, secrets that will shake the fabric of everything Mephiston is and challenge his understanding of the darkness lurking within him...