Come Name the Stars With Me

Soulmate AU
Whether you call it a soulmark, a lovelace, a bondmark, or anything in between, everyone has one. One right handed person for every left handed person and a corresponding mark on their chests that is a perfect match. However, soulmarks don't prevent tragedy or mistakes or happenstance, and sometimes soulmates are destined to be apart.
John's lovelace is lost to a bullet. Sherlock seems destined to never find his match.
Sometimes, happy endings are elusive. That doesn't mean you stop believing in them.