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.