From the airport they took a taxi to the waterfront. They’d brought no luggage. From the safety of a concrete wharf, the Beagle Channel did indeed look forbiddingly cold, a flat gray stripe of sea lapped at by glaciers on either side. But they couldn’t do anything from dry land. For the actual transformation they’d have to be in deep water.

Chartering a boat would have been the sensible thing to do, if they were tourists, or sport fishermen, or smugglers. But Quentin and Plum were magicians, so they waited until midnight, then cast spells on their shoes and hiked out onto the channel on foot.

It was tricky at first, till they made it out through the mercifully light surf and got used to the rhythm of the swells. It was only their shoes that were buoyant, so if they fell over they’d get wet like anybody else. Once they were a couple hundred yards from shore, out beyond the glow of the lights along the beach, it got quiet and very dark and very cold.

“I feel vaguely blasphemous doing this,” Plum said. “Like, only Jesus is allowed to do this.”

“I really don’t think he’d mind.”

“How do you know what Jesus would mind?” She was silent for a minute, concentrating on the walking. It was not wholly unlike trying to walk on a black, cold, unusually violent bouncy castle. “Did you like Brakebills South?”

“I don’t think anybody likes it. But it was good for me. I learned a lot.”

“Yeah. I liked it when we were animals.”

“That was good. Did they turn you into foxes?”

She shook her head.

“Bears and seals. For some reason they don’t do foxes anymore.”

When they’d gotten on the plane that morning Brakebills South had seemed very far away, but now they were here, just a short splash across the Drake Passage from Antarctica, and suddenly it was very close, and his memories of it felt very fresh. They’d been so innocent then, he and Alice, even after what happened when they were foxes. Their feelings had been so big and raw and urgent, and they’d had absolutely no idea what to do with them. He wished he had it to do over again. He would try to be a nicer, stronger person.

Except that wasn’t quite it. What he really wished was that he had Alice back now, in the present.

“Did you do that thing at the end, where you race to the pole?” Plum said. “I bet you did.”

“Yup. You win.”

Plum just seemed excited about going back.

“I bet you got there first.”

“That one you lose.”

“Ha!” Her laughter got lost among the waves. “I can’t believe the great Professor Coldwater got beat to the pole! Who beat you?”

“A better magician than me. Did you win your year?”

“I sure did,” she said. “By a mile.”

The moon came up, unnaturally bright, a wafer of white phosphorus, but the black water seemed to swallow light rather than reflect it. Even a ripple was enough to trip over, so they wound up taking big exaggerated steps. Farther out from the beach the water smoothed out but the swells got bigger. The few lighted windows in Ushuaia, which shut down after ten o’clock, looked inexpressibly cozy. Fortunately they were wearing warm clothes, parkas and long underwear, which if all went according to plan they would never see again.

They hiked out about a half mile, well out into the bay. According to the nautical charts Quentin had consulted that was far enough. They stopped and bobbed up and down on the water in place, comically, not quite in sync. They’d prepared as much of the spell as they could ahead of time.

Quentin took a deep breath and rolled his shoulders. It was rare for magicians to kill themselves with their own magic, but stories that ended that way usually began something like this.

“All right?”

Plum chewed her lip and nodded.

“All right.”

Quentin peeled open a Tupperware container full of a revolting paste he’d ginned up back in New York based on whalebone dust scraped from some scrimshaw he’d bought at an antique store. They each dipped in two fingers and anointed their foreheads.

“Maybe we should stand farther apart,” Plum said. “If this works we’re going to get really big.”

“Right.”

They took a few steps back, like they were preparing to fight a duel, then faced the same direction. Quentin braced himself. Based on his memory of the goose transformation back at Brakebills he was pretty sure that this was going to be really unpleasant. He took a deep breath, held up his hands, and made a gentle downbeat, like he was cueing the start of a Mahler symphony.

It began. Surprisingly, it wasn’t that bad.

Shrinking, having the mass squeezed out of him like toothpaste out of a tube, must have been the rough part of becoming a goose, because now the opposite was happening, Quentin was expanding, and it didn’t feel that bad at all. He was inflating like a balloon, especially his head, which was getting absolutely huge. His parka strained and stretched and then burst apart in a cloud of down.

His neck and shoulders merged into his body as the Quentin-balloon grew and grew and his eyes zoomed off in opposite directions on either side of his gigantic head. His arms and hands grew more slowly, becoming proportionally smaller, then flattened and dearticulated into flippers—it was like wearing mittens—and slid smoothly down toward his waist. His legs fused together, and something very curious was going on with his feet, but he took note of this fact only in passing—it didn’t especially alarm him. The most hilarious part was his mouth: the corners raced back toward his ears so that his head was practically split in half by a fifteen-foot recurved smile.

His lower teeth melted away completely. His upper teeth lengthened and multiplied crazily into a hairy overbite, more like a mustache than teeth.

The only real moment of panic came when he toppled forward into the water and went under. His human instincts told him he was about to freeze or drown or both, but he did neither. The water was neither warm nor cold—it was nothing. It was like air. He did utter some truly epic, booming whale-sneezes before his blowhole-based respiratory system got going. But even that was kind of enjoyable.

And then everything was still. He was hanging in the void, neutrally buoyant, twenty feet below the surface. The Quentin-blimp had been launched. He was a blue whale. He was roughly as long as a basketball court. He was in a really good mood.

For a few minutes he and Plum floated next to each other, eyeball to eyeball. Then at the same time—somehow they coordinated this—they surfaced, arched their backs, sucked in gallons of air through the tops of their heads, and dove.

Quentin didn’t know when he’d ever felt so calm. Together with Plum he kicked with his flat, powerful tail and began undulating through the water. It took hardly any effort; it would have taken an effort to stay still. He sucked in a huge mouthful of water—his mouth and throat distended hilariously to take in more and more and more—and then squirted it out again through his weird front teeth (his baleen, that was the word) like he was spitting tobacco. It left behind a tasty residue of wriggling krill.

He’d imagined that he’d get some kind of deluxe ocean-vision as part of his package of new whale-senses, but in fact he didn’t see much better than he had as a human. With his eyes on different sides of his head his binocular depth perception was shot, and having no neck, all he could do to change the view was roll his eyes around or steer his whole humongous body. Also, unnervingly, he didn’t seem to have any eyelids anymore. He couldn’t blink. The urge decreased over time, but it never completely went away.

Once they cleared Tierra del Fuego Quentin’s sensorium expanded hugely. His world became enormous. His sight may have been crap, but his hearing was something else entirely.

To a blue whale the whole ocean was a vast resonating chamber, a great watery tympanum stretched across the earth, with fleeting, fugitive vibrations constantly zipping back and forth across and through it. Based on these Quentin could feel the shape and proportions of the world around him all the time, as if he were running invisible auditory fingertips across it. If he’d had hands he could have drawn you the coastlines of southern Chile and Antarctica and a relief map of the ocean floor in between.

And if the great blue chamber ever fell silent, he made some noise of his own. He could sing.

His throat was like a didgeridoo, or a foghorn, blasting out deep, resonant pulses and moans. The ocean was full of voices, like a switchboard, or an echo chamber, an Internet even, alive with encoded information passing through it in the form of calls and responses. The whales were always checking in with each other, and Quentin checked in too, in a language he knew without having to learn it.

They weren’t just being social. Here was a great secret: whales were spellcasters. Jesus, the entire ocean was crisscrossed with a whole lattice of submarine magic. Most of the spells took multiple whales to cast, and were designed to bend and herd large clouds of krill, and occasionally to reinforce the integrity of large ice shelves. He wondered if he’d remember all this when he was human again. He wondered, but he didn’t really care.

And there was something else—something down there in the black abyssal trenches of the ocean. Something that wanted to rise. The whales were keeping it down. What was it? An army of giant squid? Cthulhu? Some last surviving Carcharodon megalodon? Quentin never found out. He hoped he never would.

Much more than when he was a goose or a fox or a polar bear Quentin felt like himself as a whale. He had a big fat brain that was capable of running most of his personality software at the same speed he was used to. But he wasn’t the same Quentin, not exactly. Whale-Quentin was a calm, wise, contented Quentin. He was colossal, planetary, moving through the blue gloom unthreatened by anything and requiring nothing more than air through his blowhole and krill through his mouth. Drake Passage was about five hundred miles across, and it would take them two or three days to swim it, but time was an idea that he was having an increasingly hard time being interested in. Time was defined by change, and very little changed for a blue whale.

He noticed everything but was concerned with nothing. Drake Passage had the worst weather in the world, literally, but all that meant was that when he surfaced for a breath, once every fifteen minutes or so, the waves broke a little harder against his wide, slick back. He and Plum were great blue gods, flying wingtip to wingtip, and everything around them paid homage to them. Fish, jellyfish, shrimp, sharks; once he spotted a great white, swaggering along by itself through the depths with its permanent shit-eating grin. It had so many teeth it looked like it had braces. Nature’s perfect killing machine! Go on with your bad self. No, really. It’s cute.

And then the ocean floor began sloping up to meet them. He’d almost forgotten what they were doing here, fumbled it away and allowed his mind to disappear forever into the endless blue whaleness of it all. But no: they were here for a reason.

This was always going to be the worst part. They were going to have to deliberately beach themselves, hopefully on nice soft sand, but more likely on some rocky shale, or worse. They just had to hope their skins were thick enough, and the terrain gentle enough, that their delicately flanged stomachs didn’t get shredded in the process. They moaned a bit at each other, as one does, then they aimed themselves at the Antarctic coastline.

As they got closer emergency calls came in from some distant pod, warning them off, urging them to turn back for deeper water. Look out! Don’t do it! It was surprisingly hard to ignore them—he felt like he was the pilot of a falling 747 and the air traffic controllers were begging him to for God’s sake pull up, pull up! But they stayed the course, churning with their tails, pouring on speed, their massive bodies bulling through the water. If they’d had teeth they would have gritted them.

Then Quentin was lying facedown on black stones under a white sky, naked, with the weak surf of the Southern Ocean washing fiery-cold over his bare legs, which were already going numb. It felt like being born must feel, being spat out of the warm, enveloping, sustaining sea and up into the bright searing cold world. In short it sucked.

Quentin did the one thing he knew would feel good: he shut his eyes for the first time in three days and kept them shut for a good minute. He’d missed his eyelids.

Plum was lying next to him. A minute ago he wouldn’t have had to turn his head to look at her, but now he swiveled his small, pale nub of a human head in her direction. She looked back at him, pale and shivering.

“Final leg,” he said thickly.

Huh: lips and teeth. What a concept. He pushed at them clumsily with his tongue.

“Final leg,” she said.

Quentin levered himself up off the shale and immediately fell over. Gravity, my old enemy. What a stupid way to locomote. Standing up felt like trying to balance a telephone pole on one end.

They were on a narrow curving beach, black pebbles and gray sand; it was just about the least tropical beach in the world. They were both naked, and there might have been a time when, as a human male, he was at least notionally interested in the sight of Plum without her clothes on, but he was still mentally more than half cetacean, and the relative nakedness or clothed-ness of a human of either sex really could not have been more beside the point to him. He could barely remember what they were doing here.

Fortunately they’d talked through what would happen next, drilled it into their brains, which they knew would not be functioning at full capacity. They both began searching through the rocks and tide marks, heads down. This had to be done quickly, before hypothermia set in. Quentin reeled like a drunk, cutting his strange, unbearably soft yellow-pink feet on the unsympathetic rocks, until—there. A feather. White flecked with gray. He plucked it out of a mass of sticky, smelly sea-trash. No time to be picky. Basically anything but a penguin would do.