Felix thought about it, then shook his head. ‘You decide. Anything from a brand-new phylum will be fine by me.’

The flight from Toronto touched down in Los Angeles and Honolulu before terminating in Sydney. Prabir changed planes for Darwin without leaving the airport. Choosing this route over Tokyo and Manila had been purely a matter of schedules and ticket prices, but as the red earth below gave way to verdant pasture and great mirrors of water, it was impossible not to dwell upon how close he was coming to retracing his steps away from the island. The boat full of refugees from Yamdena had landed in Darwin, and he and Madhusree had been flown back there from Exmouth before finally leaving the country via Sydney. The more he thought about it, the more he wished he’d gone out of his way to avoid these signposts; the last thing he wanted to do was descend systematically through the layers of his past, as if he was indulging in some kind of deliberate act of regression. He should have swooped down from Toronto by an unfamiliar route, and arrived in Ambon feeling as much like a stranger as possible.

He stepped out of the terminal at Darwin into a blast of tropical heat and humidity. It was barely half an hour later, local time, than it had been in Toronto when he left; even with three stops along the way, he’d almost kept pace with the turning of the Earth. The sky was full of threatening clouds, which seemed to spread the glare of the afternoon sun rather than diminish it. February was the middle of the wet season here, as it was in most of the former Indonesia, but Madhusree’s expedition wasn’t mistimed; in the Moluccas the pattern of the monsoon winds was reversed, and there it would be musim teduh, the calm season, the season for travel.

The flight to Ambon left the next morning. Prabir slung his backpack over his shoulders and started walking, ignoring the bus that was waiting to take passengers into the city centre. Once he checked into the hotel he’d probably fall asleep immediately, but if he could hold off until early evening he’d be able to start the next day refreshed and in synch. With six hours to kill and no interest in window shopping, the simplest method he could think of to stave off boredom would be to wander through the city on foot. His notepad had already acquired a local street map, so he was in no danger of getting lost.

He headed north out of the airport precinct, past playing fields and a cemetery, into a stretch of calm green tropical suburbia. At first he felt self-conscious when he passed other pedestrians—the size of his backpack marked him clearly as a tourist—but no one gave him a second glance. It felt good to stretch his legs; the pack wasn’t heavy, and even the surreal heat was more of a novelty than a hardship.

There was nothing on these serene, palm-lined streets to remind him of the detention camp two thousand kilometres away, but as he passed what looked like the grounds of a boarding school, he recalled his parents discussing the possibility of sending him to Darwin to study. If they’d had their way, he might have sat out the war here. So why hadn’t he?Had he dissuaded them somehow? Thrown some kind of tantrum? He couldn’t remember.

The afternoon downpour began, but the trees along the verge gave plenty of cover and his pack was waterproof. He kept walking north, away from the hotel. The earthy smell of the air as it rained made him ache with a kind of frustrated nostalgia: he couldn’t decide whether the scent of the storm reminded him of Calcutta, the island, or just Darwin itself.

The answer came a few minutes later, when the road ended at a hospital. He stood in the rain, staring at the entrance. He would never have recognised the building by sight alone, but he knew that he’d been here before.

His mother had been in labour for eight or nine hours, starting late at night. He’d been put to bed somewhere far enough away from the delivery room that he couldn’t hear a sound, and he’d fallen asleep assuming—with a mixture of resentment and gratitude—that he’d miss out on everything. But in the morning his father had woken him and asked, ‘Do you want to see your sister being born?’

While the violence of the birth itself had unnerved him, even his mother’s suffering hadn’t been able to distract him entirely from the strangest part of what he was witnessing. Two cells that might as easily have been shed from his parents’ bodies like flakes of skin had instead succeeded in growing into an entirely new human being. That they’d done this deep inside his mother was clearly of no small consequence to her, but what struck Prabir even more forcefully than the realisation that he’d emerged in the same dramatic fashion himself was the understanding that he too had been built from nothing but air and food and ancestry, just as this child had been built, month by month back on the island, right before his eyes.

He’d long ago accepted his parents’ account of his own growth. He was not at all like a child-shaped balloon, merely swelling up with food; rather, he grew the way a city grew, with buildings and streets endlessly torn apart and reconstructed. A vast collection of templates inside him was used to assemble, from the smallest fragments of each digested meal, the molecules needed to repair and rebuild and extend every part of his body. Great fleets of microscopic couriers rode crystalline scaffolding, swam rivers thicker than treacle, and negotiated guarded portals to carry the new material to the places where it was needed.

All of this was astonishing and unsettling enough, but he’d always shied away from pursuing it to its logical conclusion. Only once Madhusree had emerged, staring uncomprehendingly into a room full of faces and lights that he knew she’d never remember, had Prabir finally seen beyond the vanishing point of his own memories. The thing he knew first-hand about her was equally true of himself: he had once not existed at all. He’d been air and water, crops and fertiliser, a mist of anonymous atoms spread across India, across the whole planet. Even the genes that had been used to build him had been kept apart until the last moment, like the torn halves of a pirate’s map of an island yet to be created.

While his mother cradled the child in her arms, his father had knelt by the bed, kissing them both, laughing and sobbing, delirious with happiness. Prabir had been relieved that his mother was no longer in agony, and quite smitten with his newborn sister, but that hadn’t stopped him from wondering what she’d actually done to deserve all this adoration. Nothing he hadn’t done himself. And that would always be true: however precocious she turned out to be, he’d had too much of a head start to be overtaken. His position was unassailable.

Unless he was working from the wrong assumptions. He’d always imagined that he’d somehow earned his parents’ love, but what if his sister’s reception was proof that you began life not with a blank slate, devoid of either merit or blame, but with a kind of unblemished record that could only be marred? In that case, the best he could hope for would be to slip no further while he waited for her to fall as far.

He’d felt ashamed of these thoughts immediately, and though that wasn’t enough to quash his jealousy, he’d resolved, there and then, never to take it out on Madhusree. If his parents continued to favour her—once the understandable fog of emotions brought on by the birth itself had cleared—then that would be their fault entirely. It was obvious that she’d played no part in it.

Nineteen and a half years later, Prabir wasn’t sure that any of these thoughts really had run through his head in the delivery room. He didn’t trust memories of sudden revelations or resolutions; it seemed more likely that he’d reached the same conclusions over a period of months, then grafted them on to his memories of the birth. Still, it made him cringe to think that he could have been so calculating and smug, however absurd it was to judge himself in retrospect by adult standards. And in one sense he couldn’t even claim to have advanced much beyond that child’s perspective: he still couldn’t untangle the reasons for his parents’ love.