The first hint of change was my son’s eye colour. At breakfast one morning a shaft of sunlight struck Kai’s eyes. They were golden brown, with irises that seemed to swallow the whites. For a moment I was sure they’d been grey before, the next second I berated myself for being the kind of dad who doesn’t even know his kid's eye colour. Better that than the other option that loomed large and threatening.

I didn’t say anything but focused on getting him to finish his cereal and out the door in time. He’d just turned thirteen, not yet in the full throes of puberty, no longer a child either. But he actually liked school, so my job wasn’t too hard most mornings. It was just that Madison had always done breakfast, and I think the daily reminder flattened our morning moods.

When he biked off I grabbed our only physical album from the shelf, to look for the kiddy pool snapshot I knew was in there. He looked up at us—Madison was still alive then—from his rubber ducky with this tranquil expression, his eyes definitely grey against the caramel glow of his face.

I immediately thought of the Chimera, the threat I’d been in denial about since I first noticed his eyes. The Chimera only struck children, whose bodies were still plastic enough to survive the change into a different species. Many people think the Chimera is nature’s way of replacing what it has lost. All the large land and sea animals are extinct. Gone are the elephant, the blue whale, the hippopotamus, the buffalo (again), along with thousands of other, less picturesque species. The Earth’s ecology is a complex machine. Even now we don’t know what made it work before we destroyed it.

But there were no tests to detect the Chimera early. I went to work simmering with anxiety, afraid that if I voiced my fears I would make them come true.

I didn’t discuss it with Kai. I should have, but my tongue floundered every time I thought of bringing it up. He’d been having a hard time with Madison’s death, not surprisingly, and I wanted him to be happy and carefree for a bit.

My days blew by in a haze of fear. I noticed every child with odd tufts of hair or discoloured nails. I worked harder than I ever had just so I could get home in time to eat dinner with Kai.

One morning Kai only grunted when I asked how he’d slept.

I winced at the look of surprise and hurt on his face, still sweet and round with those all-gold eyes, no whites anywhere.

“Kai?” I said. “What’s up?”

I knew with absolute certainty what he wanted to say: “Dad, I can’t talk! My tongue doesn’t work!”

His face turned purple with effort. He grabbed my forearm with his hot, sticky hands and grunt-shouted at me.

He looked six instead of thirteen, overwhelmed by this sudden powerlessness.

“Kai,” I said. Why hadn’t I spoken before? Because I thought he was too young. Because I wanted to protect him from the uncertainty. And now I had hardly any time left. His understanding of the spoken word would leave him as surely as his grey eyes.

“I think it’s the Chimera.”

He shook his head violently. He must have thought of it himself. He was a smart kid and his school had been stricken by cases as much as any school on the planet, about 1% of the children so far. “I’m so sorry,” I said.

He was silent. Tears dripped down his face. I opened my arms and he burrowed into them like a toddler. There was no cure. We didn’t even know which virus or activated junk gene caused it, although the blogosphere was rife with speculation. Speculation was all we had, because science takes time. The disease needs years to fully develop. It has to change every cell in his body.

My heart broke when he stepped out of the embrace with a look at the clock and got his backpack. As if getting to school on time was important now. He’d never finish school. When his transformation was done, he’d be sent to whatever place on Earth his new species inhabited.

When he came home from school, covered in dirt, scrapes, and bruises, because kids are merciless, I set him down at dinner. “I’m going to quit my job,” I said. “You don’t have to go to school anymore. We can do fun things together as long as possible.”

Kai shook his head again, in that new, violent way. He grabbed a pad and started writing. I felt like such an idiot for not thinking of that. His fine throat and tongue motor control was gone, but not his writing. Yet. “I want to stay in school,” he wrote. “I want to be normal.”

My face buckled and cracked. What a terrible idea. Wasn’t today’s experience enough to know that normal no longer applied to him? He couldn’t possibly want to go through that every day.

I didn’t need to say what I thought. He frowned as he deduced my reaction. He was such a smart kid. That was going to go, too.

“What did the other Chimera kids in school do?” I asked, playing for time. My answer was going to be vital to our relationship.

He shrugged and waggled his left hand first, then his right hand. Some stayed, I translated, some stayed away. I looked at him for a long time. I couldn’t treat him as a child any more. Most thirteen-year-old animals are adults.

I took a deep breath and said the hardest words ever. “Kai, I have no control over what school and the Chimera Disease Center are going to say. But until that time, it’s your choice. I will support whatever you want.”

His face crumpled and he ran out of the room, too old and too proud to let me see his tears.

Later that day, the school contacted me to tell me they had alerted the CDC. They arrived that same evening, suited up and all, to take Kai away. I didn’t appreciate the circus they put me and Kai through, but I knew better than to protest. There have been cases of Chimera where the parents lost custody trying to keep their kid out of the maelstrom.

The long and short of it: the diagnosis was confirmed. Huang vs. School District of Columbia had ruled in favour of Huang a couple of years ago, so Kai still retained his right to education.

Kai went back to school, but already he was getting clumsy on his bike, his hands thickening into we didn’t know what kind of paw or hoof or claw. His writing became nearly illegible, until one day he gave up on it. He ate voraciously of everything except meat, growing at a vast rate in all directions. Clearly he wasn’t going to be anything small or delicate. Or carnivorous.

A bump swelled between his eyebrows. The skin felt rough. We pored over animal atlases and picture books. Some librarian had pasted red stickers over the large extinct mammals, which was pretty much all of them by now. Giraffe, lion, orca.

What if he turned into a walrus? Or a bottlenose dolphin? How would I ever keep track of him?

Kai threw the books away and went digging for his old picture books. I wondered about his temper. But he returned with a shoddy children’s book, the kind you get for free, with garishly coloured cartoon animals. He pointed at the unicorn, from its golden spiraling horn to his own tiny bump.

My heart sank. I picked up the fallen books and found the rhinoceros.

Kai refused to look at it, working his lower jaw from side to side in a peculiar grimace. In his coarsened, yellowing teeth and budding tusks I saw proof of my suspicion.

I read out loud to him. “The rhinoceros is a herbivore. It’s thought to be the second-biggest land mammal in the world. The rhino averages about 1.5 tons in weight and has a tough skin that is roughly ¾-inch thick. It has a large horn in the middle of its face and some species have a second smaller horn above the larger one.”

Kai crept back on my lap, although by now he weighed almost twice as much as me, and pointed at the words with his clumped hand, the fingers merging with the palm. “Unh! Unh!”

I pushed away premature plans of how to transport him to Africa and started over. “The rhinoceros is a herbivore …”

My voice burred on, thick and clogged. Maybe I could become a ranger at Kruger National Park.