I clean the YMCA pool from three to six AM. Five years. I know every echo in that building.

Tuesday, I unlocked the front doors at three fifty-eight. Alarm still armed. Nobody in, nobody out since the night manager left at eleven.

I'm walking the deck with the skimmer when I see them. Wet footprints. Adult size. Coming out of the men's locker room.

The locker room I hadn't unlocked yet.

I check the key in my hand. Still warm from my pocket. The door is locked. I jiggle the handle twice.

The prints lead straight to the edge of the deep end. They stop there. They don't come back.

And then, from the bottom of the pool, something taps the underwater light. Three times. Polite. Like it's asking.