The Temporal Clock Tower (5E)

From the introduction:

A mysterious obsidian obelisk has appeared on the outskirts of the kingdom, and in its wake unusual temporal effects have begun to affect the surrounding countryside and nearby villages. Pockets of “increased time passage” have been accelerating the aging process of creatures and structures. Sometimes those affected age only by a few years, and other times they are aged to ruin, decay, and dust. The range of the effects seem to be expanding, and panic among the locals has prompted mass migrations as villagers flee from the tower’s curse.