After Archangels materialise over the bloodbaths of WWII, they take up residence in most of the world's major cities. But what would happen if, more than quarter of a century later, something somehow managed to kill these supreme beings? Killarney knows and, as an agent working for the Bureau, a British agency that's so secret it doesn't officially exist, she finds herself embroiled in the consequences as, one by one, the Archangels die.

Assigned to trace a missing cryptographer thought to have information on the murders, she travels from England, through France, heading for the frozen wastes of the USSR. But there's an unknown third party intent on stopping her, and there's God, who also has an agenda. Not knowing who is friend and who is foe, and with only a brief glimpse of a swastika on angel wings as solid information, Killarney struggles to remain alive long enough to glean sufficient information to put together the pieces of the puzzle and complete what is, without them, an impossible mission.