“DID YOU HEAR THAT?” EMMET ASKED.

“What?” Calvin answered.

“It sounded like a splash. From that way.” He pointed toward the eastern point of the island. “Or maybe that way.”

“When you’re around water you tend to hear splashes,” Calvin said patiently.

“Ha. Very funny. This alligator thing is freaking me out.”

“Look, you can’t be like that. Ninety-nine percent of the time, an alligator is not going to view you as either a threat or a meal. If you don’t do something stupid, like get between a mother and her babies, or corner it, or poke it with a stick, or try to play cards with it, they’re just going to slip into the water and swim away. Gators are a fact of life down here. Besides, didn’t you have grizzly bears in Montana?” Calvin asked.

“Yes. But you didn’t tend to see grizzly bears sunning themselves by the side of the road. And they have fewer teeth. And what is this ‘ninety-nine percent’ stuff? What about the other one percent?” Emmet said.

“The other one percent of the time you’re gator bait,” Calvin said matter-of-factly. They reached the other side of the small island. Nearby, a nesting cormorant took flight. The flap of wings and resulting squawk made Emmet jump. He took a deep breath to calm his nerves. Apollo jerked the leash and barked. His dislike of birds was intense.

“Are you always such a comedian?” Emmet asked.

Calvin shrugged. He watched the cormorant circle the sky above them.

“Come on,” he said. “We’re making mama bird nervous.”

“She’s not alone,” Emmet said.

They walked along the shore, Apollo in strange-odor sensory overload, darting back and forth, smelling everything and nothing all at once. Now they stood on the north end. The whole island was maybe seventy-five yards wide and one hundred yards long. Calvin recited the names of trees, plants, and birds. Emmet couldn’t remember ever seeing so many different species of birds in one place. His dad, the bird nerd, was probably going to pass out. There were anhinga, egrets, herons, and ospreys. It was enough to drive poor Apollo to apoplexy.

Emmet couldn’t say exactly when his feeling of being watched started. It may have been when Apollo stopped and alerted, growling and nearly pulling free from the leash. The dog peered into the trees massed on the center of the island — small, excited yips escaping his throat. Apollo was straining so hard at his leash, Emmet was forced to lean back to keep from stumbling.

Or it might have been the feeling, a tickle along the back of his neck. Calvin didn’t seem to notice, and for a brief moment Emmet saw how different Calvin was out in the swamp compared to how he appeared earlier in the day. There was a peaceful look on his face. He clearly felt at home here.

Emmet heard a noise, a large rustling sound in the interior of the island, high in the trees.

“Did you hear that?” Emmet asked.

“What?”

“That noise, like something in the treetops,” Emmet said.

“I didn’t hear anything. Relax. It’s probably just a bird.”

Apollo jerked at the leash and whined now, ready to hurl all twenty pounds of his righteous fury upon whatever was stalking them. Emmet looked, and this time there was more and louder rustling, and he saw branches and leaves moving.

“There’s something there. And it’s coming this way. Seriously, dude,” Emmet said.

Calvin looked. His eyes narrowed and he studied the copse of trees, his head cocked, listening. The wind was in their faces, and Apollo was sniffing like he was a contestant in the world’s-most-sniffingest-dog contest.

“Probably just a bird,” Calvin said.

“I don’t think so,” Emmet said.

“Based on what?” Calvin asked. The words were hardly out of his mouth before they heard a strange cross between a grunt and what sounded like an extremely angry lion.

“Was that a gator?” Emmet asked, reaching down and scooping Apollo up in his arms. The dog struggled to get free. Emmet wrapped the leash around his wrist a few more times and told Apollo to settle down. With limited effect.

“I … don’t know. It sort of sounded like one, but not exactly….” Calvin muttered, still studying the trees. The branches of one of the taller trees, maybe fifty yards away from where they stood, clearly shook this time. The weird noise sounded again. Apollo couldn’t control himself, and let loose with a full-on onslaught of barks, still wiggling and trying to free himself from Emmet’s grasp.

Curiously, the branches stopped moving, and the strange call was silenced by Apollo’s anger. This only made Emmet feel more uneasy, because the feeling of being watched was impossible to ignore. Now he felt a little bit like a fly trying to get free from a spider’s web, but the spider was getting closer.

“I think we should go back to the boat,” Calvin said quietly.

“I’m not going back through there!” Emmet said.

“No. We’ll walk along the shore, circle around that way,” Calvin said. He moved to the water line, keeping his eyes on the trees, which only made Emmet feel more creeped out.

“What do you think it is?”

Calvin shrugged, but was picking up his pace. Emmet was still carrying Apollo, and struggled to keep up while contending with his squirming dog.

“I’m pretty sure it was a gator,” Calvin said. “Might be a nest in there. Mama calling to the babies, probably, except …”

“Except what? And wait a minute! We just walked through there a little while ago. Did we go past a nest?” Emmet was freaking out a little bit.

“We could have … it’s just … it’s a little early in the spring for eggs to hatch,” Calvin said.

“But baby alligators … don’t they just run to the water after they hatch, like sea turtles or something?” Emmet asked.

“No. Mama gators take care of their young. They stay near the nest until they’re big enough to survive on their own. If there’s trouble or a predator, she’ll call them and they will swim or crawl into her mouth for protection,” Calvin replied.

“You’re kidding!”

“Not about gators,” Calvin said.

“No, I suppose not. But what do you think that was in the trees? They can’t climb, can they?”

“No, they can’t climb. I’m not sure what it is. It might be a panther,” Calvin said. The boat lay up ahead, bobbing gently in the water. It was a welcome sight to Emmet. Then he remembered that Calvin just said panther.

“A panther? What kind of island did you bring me to?”

“I’m just guessing. It might have been on the southern end and heard us, or smelled us when we walked through. It’s probably just curious. Still, they’re critically endangered down here, so we should leave it alone,” Calvin said.

“Gladly,” Emmet said.

Apollo was still a little furry ball of rage, barking and growling while he struggled mightily to be free. When they stepped into the boat, Emmet set the dog in the seat and hooked his leash to it. Apollo stood up, his body rigid, growling toward the trees in the center of the island. Calvin untied the line from the mangrove root and took his seat at the tiller. He pushed the ignition button and there was a whirring, then a clicking sound.

“Dang,” Calvin said.

“What?” Emmet said.

“I don’t know … yet.” He tried the button again and was rewarded with another whir and more clicks. Calvin knelt behind his seat and pulled up a panel on the deck over the engine compartment. He jiggled some wires and turned a couple of knobs and tried the ignition again. Nothing.

“I’m going to have to radio base and arrange for a tow. We …” He stopped speaking and Emmet looked back at him.

“What?” Emmet asked.

“The microphone is gone,” Calvin said.

“How?”

“I don’t know. It was there when we left,” Calvin said.

Right then, Apollo went berserk. He barked crazily and jumped off the seat, running the length of his leash until it jerked him to a stop. Calvin and Emmet looked up to find what occupied his attention. They both immediately wished they hadn’t.

Crawling slowly out of the trees and heading toward the boat across the sand came not one but two creatures just like the one that lay in Dr. Geaux’s lab. As terrifying as the dead one was, alive they were even more frightening. One of them opened its mouth and bugled with the awful croaking roar they heard earlier.

Both of them were headed straight for the boat.