Without looking at him, she started on the first deck of cabins, methodically working her way down the row of doors. Spiders wove curtains of cobwebs in every corner. As the ship had smashed into the mud, the Beauvallet had tilted to starboard, giving everything a drunken, funhouse air.

Down the other side of the corridor, Hessa was also checking cabins.

‘Nothing,’ she said, as they met at the end. ‘Just a lot of dirt.’

‘Next level,’ Casey demanded, then froze. A clang? A knock? Far in the distance? Or nothing stirring at all.

‘What is it?’ Ed whispered.

‘Nothing,’ Casey said in the end. ‘Nothing.’

They kept going, climbing to the next floor, and the next. Dragging open double doors to a huge casino, the fruit machines ripped away. Then a bar like an airport lounge, a vast gym, and even a table tennis room. Nothing.

As she searched, Casey imagined the thousands of people on this ship, once. The staff scurrying, neat in their uniforms, the tinkle of music in every corner, the sea, all around, quite forgotten. She saw the bright smiles, the formalised fun, the scarlet umbrellas in cochineal cocktails.

Now, the air was stale. A coffin, opened. In one bedroom, Casey couldn’t bear it any longer, sprinting to open a porthole, tearing at the catch. She leaned out into the night breeze, fingers digging into her palms.

Outside, the smell of oil was sharp, carried along by the wind. She guessed it must be from one of the old oil storage units, just down the beach. In 2016, one of those units exploded on the beach at Gadani, in Pakistan. Dozens of workers killed by just one mistake. Casey imagined the searing flames, the men trapped by steel designed to withstand an ocean. It took days to find all the bodies in the wreck.

‘Come on,’ she muttered to herself, and turned back to the next cabin.

Up another flight of stairs to The State Rooms, twirls and curlicues on a plaque. These rooms were larger, easier to search, the rats scuttling away as Casey yanked open the doors. She paused for a moment in a slight breath of wind, pushing her hair back from a forehead wet with sweat. Beyond double doors, the end of this corridor was sliced off, the black void gaping empty. From the corridor, it was a hundred-foot drop straight down to the beach.

In the next corridor, Ed was checking rooms methodically.

Casey pushed open another door. This dusty king-size bed still had its sheets and its blankets, the striped sofas gathered round a coffee table. Through torn curtains, the balcony peered out on the darkest of nights.

Still, nothing.

Up another flight of stairs, mould blossoming on sweeping treads. A chandelier glittered briefly in the torchlight.

The Emperor Suite, shouted a nameplate, and Casey turned towards it, feet heavy.

But there . . .

‘Ed! Hessa! Look!’

A huge bolt had been welded onto the door, the steel scarred brightly new.