Blood Angels Librarian Callistarius, accustomed to battling nightmarish Genestealers on space hulks, faces an unsurpassed foe. While boarding an unnamed ship as part of his squad of Terminator battle-brothers, Callistarius finds himself attacked by a creature possessing enormous psychic power, which awakens the Librarian's inner demons. While the Librarian and his brothers fend off a psychic attack from an unknown creature, they must find this creature and destroy it before they are all overcome by an uncontrollable black rage.