We drain the pool the last Sunday of September, always, and for three nights after we don't go near the deep end. That's the rule. Dad never explains it beyond, "because your gran said so," and Gran's been gone eleven years now, so there's no asking her either.
We run Brintley Baths, the three of us, Dad and me and my brother Connor, since Mum stopped coming down after her hip. It's not much of a place. Six lanes, a leisure end with a broken flume, chlorine smell that gets into your coat and stays there through two washes. But it's ours, and every September we empty it for the winter service, and every September the water stays warm for three days after it's gone.
You can put your hand flat on the tiles at the shallow end and feel it, like a radiator under a blanket. Connor tested it with the thermometer gun two years back — twenty-nine degrees, on a floor with no water on it and no water in the pipes. Dad took the gun off him and didn't say anything for the rest of the shift. He didn't say anything the next day either, actually, not about that. He was in one of his quiet moods that week for a different reason, something to do with the boiler contract, I never got the whole story.
Tonight's the third night. We do the walk-round at eleven like always. Check the boiler room, check the fire doors, check the pool cover's weighted down at all four corners with the sandbags. That's the actual rule, if you want the specific bit: cover on, sandbags down, nobody stands on the pool floor between the draining and the third dawn. Dad's granddad built this place in the fifties and there's a line in the maintenance log, in his handwriting, that just says do not walk the empty basin. No reason given. We've never needed one, and Connor's taken to reading it out in this flat robot voice he does, like it's a warning from a machine, which isn't funny but he thinks it is.
At half eleven Connor goes to check the far corner because one sandbag looked light on the CCTV monitor. I tell him leave it till morning. He doesn't leave it till morning. He never does. He's twenty-two and still can't sit still through a cup of tea, Mum says he was born early and never stopped rushing.
I hear the fire door bang and I go after him because Dad's dozing in the office chair with his mouth open and somebody has to.
The pool hall at night is only lit by the emergency strips, green along the skirting, and the cover's this vast grey sheet stretched wall to wall, sagging slightly in the middle where the water used to hold it up. Connor's crouched at the deep end corner, tugging at a sandbag that's split its seam.
"It's fine," he says. "Just needs a new bag."
That's when I notice the cover isn't sagging the way it should. The dip in the middle, where the deep end drops to two metres, is rising. Slow, like something underneath is filling the shape of the water back in from the bottom up, pushing the sheet toward the ceiling in one long smooth swell. It doesn't ripple. It doesn't wobble. It just lifts.
Connor stands to look at what I'm looking at.
The swell reaches the height a diving board would clear a person from, and stops.
We don't run. I want that on record, that we don't run. We back out through the fire door the ordinary way people back out of rooms, one hand behind you for the frame, and I get the bar across it. Connor's saying something about the sandbag still needing weight, over and over, the way you say a thing when your mouth needs work to do and there's nothing else on offer.
Through the wired glass panel in the door, the cover is still risen, holding its shape, dead centre of the hall, in the dark green light. Not moving at all now. Just up, and staying up, the way a held breath stays until somebody in the room remembers to let it go.