There's a world where magic is real and the faerie stories your grandmother and great-grandmother told you are true. It's a little bit to the left of ours, even overlapping in a few places, but it's nearly impossible to get there. You or I will probably never even come close. But in the overlaps, at certain times of night or year, it is possible.

You've heard of the witching hour? That's the most common crossing time. It comes almost every night, but never at quite the same time. It's usually somewhere between midnight and two o'clock, but you can never be sure to catch it, and sometimes it can catch you unawares. It's the time of night when everything is still and quiet as could be, when time seems like an illusion and nothing feels real.

There are also the switching-days, when the court rulers change from the mild Seelie court to the much harsher Unseelie and back again. Those days are called Beltane and Samhain in that world, or May Day and Halloween in ours. Those days are the least dangerous to cross on, because all the fey are busy with the switching.

The most dangerous days to be outside on at all, let alone attempting to cross over, are the solstices, the longest and shortest days of the year. Midsummer's Eve is a festival, where nobody is safe, even in our world, let alone a human in the world to the left.

Beware of rings of mushrooms, beaches full of stones with holes, woods where you can't seem to walk in a straight line, and streams that run uphill. There, crossing can happen at any time, willingly or not.