The Cursed Clock

A clock based on advanced scientific principles of timekeeping has been making the rounds in the nobility of Frankia. Made using techniques known only to its creator, it has sown death to a good number of nobles over the short time it has been in circulation.
The clock has been recorded as first appearing in the city of Parisius. Sitting in the family home of the Duke Otto Ramnulfid. Iy seems it was part of a number of artefacts that were bought of the le Marchand clan. The latter appeared to be selling goods they had purportedly fashioned from designs from the Middle East & Far East, or at least made in those far away lands. Each seems to be cursed. A mirror lies in one house now lying in ruins, and a cube of stragne material was found in another house devoid of the inhabitants but with places covered in gore. And now this clock.
The family has noticed that once every month on the 13th, the clock slows down for the period of the Witching Hour (between the hours of 3am & 4am). Yet when this happens the rest of the period outside the house still moves as normal and the clock always marks time as usual the rest of the time.
When this happens someone tied to the house, whether servant, slave, guard, visiting guest or family member inexplicably dies. They seem to slow down and stop dropping at the last minute where they age considerably faster ageing years if not decades in a matter of moments. So far at least six separate people have died and no-one can stop it.
The clock's display glows slightly every time this seems to happen. When noticed, the Duke tried to have it stopped from physically working, damaged & destrpyed it, and getting rid of it, but it always reappears back in his meeting hall. Nothing seems to stop it, and he is now wondering what it will do when it finishes with his family.
Written on the inside in miniscule letters is a verse written in an relatively unknown language. A rough translation by those that klnow such dangerous languages as this states that it translates as "On the time of the Witching Hour, a life will reach it's end, and when the thirteenth is achieved, then the time will end." Exactly what this implies is worrying to those who have seen it, and are trying to work out the actual meaning before it takes any more lives.

"Those items that the le Marchand family peddle in... I wouldn't have any near me. I don't trust them. Misfortune follows those devices, and no matter what they are it's just not worth it. That's why none has been stolen or handled by us."
Floki the Tramp, in the Slinky Seine.