Add a subrule to “Artifacts” called “Scrying”:-

As a weekly action, a Believer (the “Scryer”) may attempt to Scry the date of the end of the world using an Artifact that they have access to, by submitting an Order which names the Cult whose Artifacts they will use in the ritual.

If the specified Cult has no Artifacts, then the Scrying fails and the Believer is informed of this. Otherwise, upon processing such an Order, the Auspex shall reduce the specified Cult’s Artifacts by 1, and privately inform the Scryer of a randomly chosen date which occurs after Doomsday and before the 4th of February 2013; such a date is known as a “Dark Day”.