The twin engines contained within the double-height compartment were primitive-looking beasts, each the size of a medium truck, and Nash was astounded to see a second pair in the adjoining hull through the interconnecting hatch. No wonder this leviathan had been able to power its way around the world.

They stepped aside to let two troopers carrying plywood tea chests pass by. The opium within gave off a thick cloying smell that was resinous and earthy, reminiscent of hashish, although more bittersweet. Through the bulkhead door ahead, they saw another soldier hoisting a tea chest to his shoulder.

‘Ayolah!’ he yelled at his comrade who was escorting them. ‘Percepat!’ Hurry up!

The twin compartments were stacked from floor to ceiling with hundreds of tea chests. One had broken open, and spilling from its hessian liner were black five-kilo balls of raw gummy opium. After seven decades curing in airtight storage, it had intensified in strength. Already light-headed in the pungent fumes, Mia warned Nash to avoid the gooey mess, lest the opiate-laden oil be absorbed by his skin.

‘What was this used for?’ Nash asked Mia as they lugged their loads back.

‘Morphine,’ she grunted. ‘It must be worth a fortune.’

Rain was falling heavily through the ragged square of daylight when they reached the stern. The water was now lapping their waists, and in the press of slippery bodies passing up tea chests, Nash’s claustrophobia felt like thick treacle slowly filling him up inside.

They went back for another load, and when they returned, the water was noticeably higher. A nervy trooper tried to argue his way out, but the NCO angrily ordered him back. Nash knew the stern would be underwater in ten minutes. What worried him more was the overflow. When that hit, anyone stuck down here without air or lights was doomed.

‘We’ve got to get out of here,’ he told their guard, rapping on the curved steel above.

‘Lebih dalam! Lebih dalam!’ added Mia for emphasis. Deeper! Deeper!

This time she could barely keep her head above the frigid black water. The Indonesians, who were of even shorter stature, were panicking.

‘Biarkan kami keluar bajingan!’ they screamed in unison. Let us out, motherfucker!

The NCO yelled at them to be quiet so he could hear the walkie-talkie. At last, he nodded, then kneeled to pull the first man out. When it was their turn, Nash pushed Mia up, and then she helped pull him out.

They stood upslope of the shivering troopers while the cargo net, laden with tea chests, ascended in the driving rain. Nash’s eyes were fixed on the jade-green water creeping swiftly towards the hole in the deck.