It wasn't an accident.
I saw what you did when you thought no one was looking, and I followed you down that alley. I admit that I didn't expect the little door hidden in the shadows. You hadn't noticed me, so I listened to how you secured entry and waited a few minutes to repeat you.
Once inside, it didn't take very long to find you again. You seemed to know everyone there. I had never been in a literal hole in the wall before, but you know how much I love an adventure. Nearly as much as I love pursuing a mystery to find an Interesting Person.
Since you knew everyone--or appeared to--I stood out. Not one to leave a stranger lurking in the corner, clearly lost, you greeted me cheerfully. I told the truth: I was new. You were delighted to show me around this place into which I hadn't technically been invited.
Neither of us knew how important that meeting would be. The world will never know the things we've done together, but I do believe it's finally time to confess that I was an intruder in your world, drawn in by such an unexpected act.
Don't worry. I'll never tell anyone what it was, of course.
Just as I know you'll never tell them what I am.
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This was written in response to one of those "Tell everyone how we met, only lie" memes on Facebook that got away from me.