A/N: Just a bit of a super-late-for-the-challenge drabble. Super sweet, super fluffy, rated K+. Enjoy!
It's unintentional; neither of them pay particular attention to holidays outside of Christmas and Halloween (Molly's never missed a Halloween shift and always dresses up and Sherlock not-so-secretly loves this about her). But it happens to be Valentine's Day when they share their first non-platonic, non-apologetic kiss.
There are many others kisses in their future, but that's the one they treasure the most. And every Valentine's Day after that one, until the very last one they share together many, many years in the future, Sherlock makes sure he's there to kiss his Molly.