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Most of the time, the boundary between worlds held firm. But certain times, certain places, certain conditions caused it to thin.
Samhain (October 31 – November 1):
The year’s turning, when summer died and winter was born. On this night, the boundary dissolved almost completely. The Sídhe rode out in procession, the dead walked among the living, and anything could happen. Mortals stayed inside, fires burning, iron laid across thresholds. To venture out on Samhain was to risk being taken—not killed but transformed, carried off to the Otherworld and never returned.
Mist and Fog:
Weather could thin the boundary. Fog especially—thick, white, disorienting—was suspected of being Otherworldly in origin. Travelers caught in sudden fog might emerge in different locations than expected, having walked through the edge of the Otherworld without realizing. Some never emerged, last seen walking into white blankness, voices fading, gone.
Sacred Wells:
Wells were vertical thresholds, passages from surface to depth. To peer into a well’s darkness was to look into the Otherworld. To drop an offering—coin, jewelry, weapon—into the water was to send it across the boundary, payment for healing, knowledge, or protection.
Some wells were more dangerous. They were not thresholds but doors standing open. A person who fell into such a well (or dove deliberately) might surface in an Otherworld lake, breathing water, transformed into something neither mortal nor Sídhe but stranded between.
The Between Times:
Dawn and dusk—neither day nor night—were suspect. High noon, when shadows disappeared, was a moment of crossing. Midnight, opposite and equal, was even more dangerous. These were temporal boundaries, moments when the clock’s hand paused between numbers and reality became negotiable.
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