The Officio Medicae is a division of the Adeptus Administratum that deals with all medical matters within the Imperium. Its official position on any issue is simple: "A soldier must return to their duty as quickly as possible. The enemy will not wait for them!" If a soldier's leg is torn off, it must be replaced with a crude prosthetic and the patient sent back into battle. If an arm becomes infected, it must be amputated and substituted with a primitive implant. If the lower living quarters of a hive are struck by an unknown affliction, the disease must be eradicated swiftly and efficiently, usually along with the infected themselves. Only the most valuable and renowned citizens of the Imperium can expect long-term care from the Medicae.

Epione Spes was raised in a noble family, and she had always dreamed of using her outstanding intellect for the benefit of Humanity. By a twist of fate, she was deprived of both her kin and her high status, and yet, she managed to fulfill her ambition of entering the medical profession — a science accessible only to a lucky few. Having mastered the art of diagnosis, the mysteries of pharmacopoeia, and the precise craft of chirurgery, she became an indispensable specialist in her field, only to find herself in the wrong place at the wrong time: When the Holy Inquisition came for the owners of the research station to which she had been posted, Epione Spes was considered too valuable an asset to be simply disposed of. A difficult and arduous journey then led the chirurgeon to the Holy Ordos, where her knowledge and skills found worthy use in the service of the God-Emperor and Humanity.

Upon joining the Inquisition as an acolyte, Epione soon learned of dangers and maladies that would terrify an ordinary person. But the young woman's cold, analytical mind saw more than just another nightmare in the afflictions plaguing the Calixis Sector; it saw an opportunity. And so, Epione Spes set out to hunt down the elusive disease that had struck the sector capital of Scintilla, and only the God-Emperor Himself knows how this pursuit will end.