There's a fire on the third floor. The city has stood in water since winter.

The city has been half underwater since winter, and you've been poling through what's left of it for three days, on two doors lashed together, with an oar cut from a tabletop. Your supplies ran out yesterday afternoon. One bottle of water left, and a bandage you're saving because you might need it more later.

This block used to be housing. Now it's islands of roof and upper floor, windows looking down at water that had no business being here a year ago. No lights, the whole time you've been out.

Then, on the third floor of a half-collapsed building, you see it: a window, orange, flickering. A fire, kept small, but real.

It means two things, and they weigh the same. First, somebody here has fuel to burn, which means somebody has supplies. Second, nobody keeps a fire going at this water level by accident, and people who've survived alone for months don't share it willingly.

The tide is higher tonight than usual; water is already licking the third rung of your raft, and dusk brings a current that takes anything not tied down. You have maybe an hour before paddling gets more dangerous than staying put.

You lie still in the water, thirty metres from the building, and watch a shadow cross the window once.

The fire escape is missing three rungs, and the fourth gives under your weight without quite breaking. You climb anyway, slow, one hand always on the rail, the metal cold enough to burn your fingers.

At the second-floor landing a wire runs across the stairs, barely visible, three empty cans strung along it. A warning, not a trap — whoever lives here wants to know when someone's coming, not to make sure nobody does. You lift your foot high enough to clear it, and hold your breath until the cans hang still again.

The third-floor window is boarded from inside, except for a gap barely wider than your hand. You press flat against the wall and look through.

Inside: someone, back to you, kneeling in front of a small fire built in a converted oil drum. Beside them a crate, half open. Tinned food stacked neatly, a red-cross kit still sealed, a jerrycan you recognise by its shape as drinking water. Enough to tell you this person has been planning for months, not just surviving.

They stop poking the fire and go still. Like they heard something.

Below you, far down, your raft knocks against the wall. The wind has turned.

You have maybe ten seconds before they turn around.

The crowbar swing misses you only because you step back before you've finished saying "wait." The person — a woman, maybe sixty, sleeves pushed past her elbows — holds it between you now, but she doesn't swing again.

"Who sent you," she says. Not a question. A test.

"Nobody. I saw the fire." You keep your hands open, visible, a habit the last few months have taught you well enough. "I need a bandage, maybe some food. Then I'm gone."

She studies you a long moment. The crowbar drops an inch. No further.

"The fire's not an accident," she says finally. "I keep it high enough to see from the water. Every night for four months."

"Why, if it draws people you don't want."

"Because I want it to draw one I do." She says it without looking at you, and that's when you hear it too: a second sound outside, lower than water against the wall. An engine. Small, but real, getting closer, from the same direction you came from.

The woman goes rigid. For the first time you see she's exactly as scared as you are.

"That's not who I'm waiting for," she says quietly.

"Three boats came through six weeks ago," she says, eyes fixed on the door. "Call themselves a cleanup crew. They don't take what you have. They take you, if you're young enough to work, and burn the rest so nobody can say they were here."

The engine's closer now, still uneven, like someone threading a course through wreckage rather than heading straight in. You find yourself counting the seconds between sounds without meaning to, the way you've counted every noise bigger than you for months now.

"I keep the fire anyway," she says. "Because my son knows I do. He left in spring to find insulin, for his daughter, down in Block C. He said he'd come back as long as he could still see the light."

She says it like a fact, not a hope, but the hand holding the crowbar has started to shake, just slightly, and you notice for the first time how thin her wrists are under the sleeve.

The engine noise grows, then fades, then cuts out entirely, somewhere below you, too close to be chance.

The woman doesn't put the light out of her eyes, but she reaches for a second weapon, a hatchet leaning against the crate, and presses it into your hand without a word.

Outside, on the water, you can hear voices now. More than one.