An Ultramarines Apothecary tries to save precious gene-seed from an ancient and malevolent traitor in a new Ultramarines story by Graham McNeill. Wounded Ultramarines Apothecary Isstvan Cantaro, the last survivor of an attack on his ship, seeks to protect the sacred gene-seed of his battle-brothers from the vile intent of Dzyban of the Emperor's Children, and the hundreds of cultists now stalking the ship. The most sacred duty of the Space Marine Apothecary – to keep safe the genetic material from which new Space Marines are made – goes under the spotlight. Graham McNeill has crafted a tight, tense tale with twist after twist and a great insight into these most noble of Adeptus Astartes warriors.