At the bottom of the grand staircase there was a lobby with two passages running parallel towards the back of the ship. On one side of each corridor, the cabins looked out over the sea. On the opposite side, the cabins on the inside of the ship – cheaper by far – had no windows.

Halfway down each corridor, there was a set of double doors. Casey knew that beyond them the ship had been sliced from deck to hull, during its slow, deliberate shipwreck. Those corridors led to nothing but a plunging fall in the dark.

‘Make sure,’ she whispered to Hessa, ‘that no one goes that way.’

Next to the passages running along the ship, doors on either side of the lobby opened on to smaller flights of stairs that ran down both sides of the Beauvallet. Left or right, port or starboard – the toss of the coin that meant everything.

Casey hurried over to one of the gaping lift shafts. Silence. She crossed the lobby and listened at the other.

Casey felt the girls’ eyes on her, their fear almost tangible. Nothing. Please nothing. But, far below, so far below, she heard the scrape of a door echo up the shaft.

‘That way,’ she whispered to Hessa. ‘Down those stairs as quietly as you can. Go to the fishing boat.’

‘But . . .’

‘Go.’

‘I’ll look out for you.’

The girls moved fast. One chance, seized. Casey felt rather than heard the women scurry down the stairs. One second, she was surrounded by human bodies, and the next moment the air was empty, only Ed beside her.

Casey waited a second, then crossed back over to the other staircase.

‘Bonjour,’ she shouted down. ‘Qui est là?’

There was a shocked scuffle below, a Bengali voice, a man, shouting in anger.

‘That’s Raz.’ Casey recognised the voice. ‘He must have come from Dhaka.’

‘Now what?’ Ed whispered.

‘We wait.’ She tried to smile at him. ‘We’ll be fine.’

‘You’re lying.’ His voice was light.

‘Why would I lie to you?’ For a second, Casey felt a shimmer of hysteria.

‘Force of habit?’ Their eyes met, that smile.

They could hear several people racing up the stairs towards them, shouting. There was pure rage in Raz’s voice, the charm all gone. Here was anger, violent anger, and Casey felt her laughter drain away. Raz would kill, she knew, rather than let them escape.

She tried to calculate how long it would take the others to flee down the opposite stairs.

Please, she begged. Don’t let them have left a guard at the bottom of the stairs. Please.