Red Cherry Wine

When a person turned 10, a marker would appear on their wrist. The marker, a black or white moon, would start as a new moon, and phase to a full moon. The phases happened like the real moon, but spread out a lot further apart.
Both markers phased at the same time, whenever two soul mate got close enough to each other.
Upon meeting, the marker would become a permanent full moon, a simple black or white circle.
There was one problem: the phasing hurt. What would start a simple burn, soon became a blinding heat that usually sent a person to his knees.
Sometimes though, in rare cases, the markers didn't phase at all. This usually meant that the person's soul mate was no longer living.