THE LIGHT WAS REALLY BRIGHT IN EMMET’S EYES. A doctor whose name Emmet had already forgotten was holding one of those tiny flashlights about an inch from his eyeball. The doctor asked Emmet to follow his finger back and forth without moving his head. Emmet was still hyped up from nearly being eaten by a gigantic, laughing, saber-toothed whatchamacallit. All the little tests were annoying.

“I don’t see any signs of a concussion, but there’s a nasty bump on the back of his head. I’d like to keep him overnight for observation,” Dr. What’s-His-Name told Emmet’s dad.

“Okay,” Dr. Doyle answered tiredly.

“But, Dad! I don’t want to stay in the stu —” His dad interrupted him by holding his hand up. Dr. Doyle was generally likeable and easygoing about most things. But when he was wearing his parent pants, he was not open to discussing anything. This was one of those times. When his dad held the hand up while Emmet was complaining, whining, or talking, the discussion was over.

“You’re staying. And I’m staying with you,” he said.

“I’m afraid that’s not allowed,” the doctor said. He was busy writing something in a chart hanging from Emmet’s bed. He wasn’t paying attention as Dr. Doyle strolled up to him, close enough to invade his personal space.

“Doctor,” he said quietly. “Tonight something tried to kill my son and me. It almost succeeded. If you think you’re getting me out of this room tonight, you’re going to need a lot more muscle.”

Dr. Geaux was standing off to the side with Calvin. They had met Emmet and his dad at the hospital. Dr. Geaux looked weary and worried. Calvin’s eyes were a little more wide open than usual. In Calvin, this meant he was alarmed and concerned. Otherwise he just seemed like regular Calvin, sitting in a chair not saying much.

“Ben,” Dr. Geaux started. “I can have a couple officers —”

Dr. Doyle gave Dr. Geaux the hand.

“No, Rosalita,” he said. Probably more sternly than he meant to, Emmet thought. “Thank you. If you want officers outside in the hall, fine. But I’m not leaving my son’s side.”

“That violates hospital policy. I’m afraid for the patient’s sake —” the doctor started speaking again, but Dr. Doyle stepped closer, his nose now inches from the doctor’s.

“Maybe I didn’t make myself clear: I’m not leaving.”

Truthfully, Emmet’s dad was kind of surprising him. This was a side of him he’d never seen before. Benton Doyle was not what anyone would call a tough guy. But he was an avid outdoorsman, really smart, and he loved Emmet. In Montana, he’d hiked all over the mountains and sometimes led search-and-rescue teams to find lost and stranded hikers. He kept himself in shape, and tonight the doctor saw something in Dr. Doyle’s eyes that made him step back.

“I’ll clear it with the hospital administrator, Doctor,” Calvin’s mom said. “This is now officially a Dr. Catalyst task force case. The usual rules no longer apply. There will be two officers stationed outside Emmet’s room at all times. No one is allowed inside without proper hospital identification. And Dr. Doyle will be staying here tonight with his son.”

“But … that …” the doctor sputtered.

“That will be all, thank you,” Dr. Geaux said.

The doctor tried to leave the room with a bit of dignity intact and failed. He scurried away and it was just the four of them.

“Well, he’s back,” Emmet said.

No one said anything. When the Muraecudas showed up, everyone gave him grief about how Dr. Catalyst had died in the swamp. And Emmet kept insisting he was alive. Eventually he was proven right. Dr. Catalyst had faked his death. Then he kept releasing more and more genetically altered species, and the only thing they all had in common was really big teeth. Huge teeth. Sharp. Quite pointy. Emmet had a suspicion that perhaps Dr. Catalyst secretly wanted to be some sort of evil dentist.

“There’s no sign of the creature anywhere nearby,” Dr. Geaux said. “Lieutenant Stukaczowski found some tracks near the canal behind your house. The photos we ran through the database don’t match any animal we have on file. Which is pretty much any animal that leaves a track. The paw prints indicate it has retractable claws like a cat, but the rest of the footpads look canine. Canines don’t catch food with claws. Cats do. This one looks like it can.”

“Well, that’s just great,” Emmet said. “Teeth and claws.”

“What’s he trying to do this time?” Calvin piped up from the corner.

“What do you mean, son?” Dr. Geaux asked.

“I mean he made the Pterogators to eliminate the snakes. The Muraecudas were created to go after lionfish. Then he said the Blood Jackets were to show us what it was like when an invasive species was unleashed on humans. What is this creature after?” he asked.

“That’s a good question. I wish I knew the answer,” Dr. Doyle said.

“It’s obvious,” Emmet said. “Dr. Catalyst has one last invasive animal he wants to get rid of.”

They all looked at him, waiting for clarification.

“Me.”