With departure looming, the images and memories Neel had tried to bar from his mind came flooding back: of Elokeshi, of his home, of his husband-less wife and fatherless child. When he dozed off, it was only to be visited by a nightmare, in which he saw himself as a castaway on the dark void of the ocean, utterly alone, severed from every human mooring. Feeling himself to be drowning, he began to toss his arms, trying to reach towards the light.

He woke to find himself sitting up, in the darkness. Gradually he became aware that there was an arm around his shoulder, holding him steady, as if in consolation: in this embrace there was more intimacy than he had ever known before, even with Elokeshi, and when a voice sounded in his ear, it was as if it were coming from within himself: 'My name Lei Leong Fatt,' it said. 'People call Ah Fatt. Ah Fatt your friend.' Those faltering, childlike words offered more comfort than was in all the poetry Neel had ever read, and more novelty too, because he had never before heard them said – and if he had, they would only have been wasted before, because he would not have been able to value them for their worth.

It was no human agency but rather a quirk of the tides that was responsible for fixing the date of the Ibis's departure. That year, as in many others, Diwali fell close to the autumn equinox. This would have had little bearing on the sailing of the Ibis if not for one of the more dangerous oddities of the waterways of Bengal: namely the bán, or bore – a tidal phenomenon that sends walls of water hurtling upriver from the coast. Bores are never more hazardous than in the periods around Holi and Diwali, when the seasons turn upon an equinoctial hinge: at those times, rising to formidable heights and travelling at great speed, the waves can pose a serious threat to the river's traffic. It was one such wave that determined when the Ibis would weigh anchor: the announcement of the hazard having been made well in time, it was decided that the schooner would ride the bore out at her moorings. Her passengers would come on board the day after.

On the river, the day began with a warning from the harbourmaster that the bore was expected around sunset. From then on, the riverfront was a-buzz with preparations: fishermen worked together to carry dinghies, pansaris and even the lighter paunchways out of the water and up the embankments, taking them beyond the river's reach. Patelis, budgerows, batelos and other river craft that were too heavy to be lifted from the water were spaced out at safe intervals, while brigs, brigantines, schooners and other ocean-going vessels struck their royal and t'gallant yards, and unbent their sails.

During his stay in Calcutta, Zachary had twice joined the crowds that gathered on the river's banks to watch the passing of the bore: he had learnt to listen for the distant murmur that heralded the wave's approach; he had watched the water rising suddenly into a great, roaring head that was topped by a foaming white mane; he had turned to see the bore go by, on its coiled and tawny haunches, racing upstream as if in pursuit of some elusive prey. He too, like the urchins along the shore, had cheered and shouted, without quite knowing why, and afterwards, like everyone else, he had felt a little twinge of embarrassment at all the excitement – because it took no more than a few minutes for the water to resume its normal flow and for the day to return to the even tenor of its ordinariness.

Although no stranger to these waves, Zachary had no shipboard experience of them, having only watched them from shore. Mr Crowle, on the other hand, was well-practised in dealing with bores and macareos, having ridden out many such, on the Irrawaddy as well as the Hooghly. The Captain put him in charge of the preparations and stayed below, letting it be known that he would not come on deck until later in the day. But as it happened, about an hour before the bore was expected, a message was received from Mr Burnham, summoning the Captain to the city on some urgent last-minute business.

As a rule, when the Captain had to be ferried ashore, it was a tindal or seacunny who rowed him over in the ship's gig – a small but handy little rowboat that was kept permanently tethered to the stern while the schooner was in port. But today the Ibis was shorthanded because many of the lashkar were still ashore, either recovering from their pre-departure excesses or making preparations for the long absence ahead. With every available hand occupied in snugging the ship down, Zachary went to Mr Crowle and offered to row the Captain's gig himself.

The offer was made on an impulse, without any forethought, and Zachary regretted it the moment it was out of his lips – for Mr Crowle took a while to chew over it, and his face darkened as he tried the taste of his conclusions.

'So what'd you think, Mr Crowle?'

'What do I think? I'll tell y'Mannikin: I don't think the skipper needs to be jibbering the kibber with yer. If he has to be rowed, then it's best I be the one to do it.'

Zachary shifted his weight uncomfortably. 'Sure. Suit yourself, Mr Crowle. Was just tryin to help.'

'Help? It's no help to anyone to have yer pitching the gammon to the skipper. Ye'll stay where ye're needed and look sharp about it too.'

This exchange was beginning to attract attention from the lascars, so Zachary brought it to an end: 'Yes, Mr Crowle. As you please.'

The first mate went off in the gig, with the Captain, while Zachary stayed on board, to oversee the lascars who were unbending the topgallants and royals. By the time the mate returned, the sky was beginning to turn colour and spectators were gathering along the embankments, to wait for the bore.

'Take y'self aft, Reid,' the first mate growled as he came aboard. 'Don't need yer swilkering about for'ard.'

Zachary shrugged this off and went aft, to the wheelhouse. The sun had set now and the fishermen onshore were hurrying to secure their upturned boats. Zachary was looking downstream, watching for the first signs of the wave, when Steward Pinto came running to the stern. 'Burra Malum calling Chhota Malum.'

'What for?'

'Problem with langar-boya.'

Zachary hurried forward to find the first mate standing between the bows, squinting at the water ahead. 'Something amiss, Mr Crowle?'

'You tell me, Reid,' said the first mate. 'What do y'see over there?'

Shading his eyes, Zachary saw that Mr Crowle was pointing to a cable that linked the schooner's bow to the underside of a buoy, some fifty feet ahead. Having been on board during the initial berthing of the Ibis, Zachary knew that the Hooghly 's bore entailed special procedures for the mooring of ocean-going sailing ships: they were usually berthed far out in the river's stream, where, instead of dropping their anchors, they were tethered between buoys anchored deep in the river's muddy bed. The holdfasts to which the ship's cables were attached lay on the underside of the buoys, beneath the water's surface, and could only be accessed by divers who were accustomed to the near-blind conditions of the muddy river. It was one such mooring-cable that had attracted Mr Crowle's attention – but Zachary was at a loss to see why, for there was not much to be seen of the rope, which disappeared underwater halfway to the buoy.

'Don't see nothing wrong, Mr Crowle.'

'Don't you now?'

There was just enough light to get another look: 'Sure don't.'

Mr Crowle's index finger rose to pick a morsel from his teeth. 'Don't say much for yer know, Mannikin. What if I told you the cable's a-foul of the buoy's anchor-chain?' He raised an eyebrow as he examined his fingernail. 'Didn't think o'that, did ye now?'