Author's Note:
Just as a warning, the time frame of Denman's return in conjunction with the development of Cleo and Lewis's relationship may not line up exactly within the show's canon. I didn't do a lot of research on that; just went with whatever felt right for the story progression. Now that you are aware... onward!
I. Into the Nightmare
Cleo woke with a start, a sickness roiling in her gut. She was drenched in sweat; a nightmare, maybe? She tried to sit up without waking Emma and Rikki, but there wasn't much room in the tent.
Something was definitely wrong. When she raised herself up, she was forced to use her elbows for support as her legs had disappeared. Why did she have a tail?
"Hey." It seemed Emma had woken after all. She nudged Cleo's arm. "Are you okay?"
"No… I have a tail!" she hissed. "I guess I was… sweating from my nightmare, but that never made me transform before!"
Emma sat up straighter and brought her legs up to her chest, afraid Cleo's condition would spread to her. "Well it is a full moon. Weirder things have happened." She fished her torch out from under her sleeping bag and flashed it across the length of Cleo's tail. It was hard to tell in the unnatural light, but everything seemed to be normal. Except for the fact that her own perspiration had caused her to change.
"I'll get Rikki up."
By the time Rikki could be shaken awake, and made alert enough to understand the situation, Cleo had cooled down, and dried off.
"I'm dry now, but I'm still not changing back!" she flung down the towel in frustration. "What if I'm like this forever?!"
"It may fade by morning?" Rikki suggested with a yawn.
"And if it doesn't?"
Rikki exhaled slowly and pursed her lips. She was very tempted to say, "Deal with it then," but she knew she'd never hear the end of it if she slept while Cleo was in such a state. So she offered to do the next best thing. "I'll get Lewis."
Lewis was much better at being startled awake than Rikki. It was barely a few moments before Rikki was ushering him into the girl's tent.
"…and she's got not a drop of moisture on her, but she's still got a tail," she explained sleepily.
"What should we do?" Emma asked.
Cleo was on the verge of tears. "If Kim or my dad sees me like this…"
"The moon pool, I guess. Until morning, at least." Lewis gestured to Cleo's predicament. "Emma… uh… I'll let you…"
Emma grabbed Cleo's tail as Lewis hoisted her by the under arms.
"Okay, there?" he whispered as they exited the tent.
"Yeah," Cleo nodded sullenly, though she sounded anything but.
As they reached the cover of the trees, Rikki saw and heard some movement coming from Kim's tent. She blinded her with the torch as she stumbled out.
"Ah! Cleo! What are you…? Oh… Rikki! What are you guys doing out here? I heard voices."
"Nothing that concerns you. Just run along back to bed, little snoop."
Kim glowered and her eyes trailed to Lewis's open and empty tent. Kim gasped. "Did Lewis and Cleo go off together?"
"No."
"That's not what I'm gonna tell Dad." She crossed her arms and was quite smug. "Unless you give me fifty dollars!"
"I'm not giving you any money!"
"Then I'm gonna go wake Dad!"
Several tense moments went by in which the two girls glared each other down, neither willing to budge. Suddenly, Kim yelped, and jumped back a step, grabbing her foot. "What was that?! Something burned me!"
"Oh, did you get bit?" Rikki asked, pretending to be concerned, "There are a lot of crazy bugs out here. I heard fire beetle bites feel just like getting burned. Might be safer in your tent."
"Yeah, right. Those aren't even a real thing. That was just… OW!" she hopped again, and as soon as her foot was back on the ground, the other one was assaulted. Soon, she was unable to stand without the pricks of what she thought were beetle bites.
The moment she was back in her tent to see to her burned feet, Rikki rushed off to follow the others.
It was no easy task, getting Cleo into the moon cave in the state she was in. Lewis could hear her sniffling as he helped to lower her down the slope, but he wasn't sure if he should say anything. Sometimes his best intentions only made it worse.
He let his hand linger on her shoulder and gave it a light squeeze before letting her slip down the tunnel to an awaiting Rikki and Emma.
When he made it down himself Cleo was sitting on the edge of the pool, gazing listlessly at the ripples on the water, her tailfin dangling just above the surface. Lewis sat next to her and gave an encouraging half-smile.
Emma was pacing while Rikki stood in the background, arms crossed in general sleepiness and boredom.
"So glad you all could make it." A disturbingly familiar voice echoed from the shadows.
Dr. Denman strolled forward, her blonde ponytail swishing leisurely behind her as she smiled. "Nice to see you, girls... Lewis," she said with emphasis. He jumped up to stand in front of Cleo as two well built men flanked Dr. Denman.
Cleo glanced from Lewis to Denman to the girls and back to Lewis with helpless eyes. Rikki and Emma each took a step back and assumed defensive positions, ready to use their powers at a moment's provocation.
"Go," Lewis said to Cleo and the girls."You'll have to swim for it."
"What about you?" she pleaded.
"Don't worry about me. I've got nothing she wants. Just get out of here while you can."
Rikki and Emma dove into the pool immediately, racing for the passage that would lead them to open water. Cleo took Lewis's hand. "Be careful, Lewis." And then she too was gone.
Dr. Denman only stood smiling.
"Give it up, Denman. You'll never catch them," he said with confidence.
She chuckled. "Oh, but I already have."
Lewis narrowed his eyes at her. "What are you talking about?"
"They seem to be having trouble down there... you might want to help them out."
Lewis huffed, but her words worried him, and after some flickering from below that indicated they had not made it out of the cave yet, he jumped into the moon pool to be of assistance.
They surfaced all at once and each of the girls began sputtering, one over the other. "She's blocked it!" "There's some sort of... grate there!" "Lewis, we're trapped! What do we do?"
"A good scientist never gives up," Denman said. "No matter the odds against him—or her as the case may be. You'd do well to remember that, Lewis."
Just as he opened his mouth to respond, the full moon started to move over the opening of the volcano. He started as a strange, mystical glow flickered beneath them from the infinite depths of the pool and grew and grew as the moon was aligned with the volcano's peak. The water churned under and around them, and tiny orbs of water separated from the pool and floated up towards the pull of the moon.
"Should we get him out of there?" one of the two large men stooped to give Lewis a hand, but Denman pulled him back. "No, leave him! I want to see what happens."
After the bubbles had abated and the moon passed over, she looked hard at Lewis. He glared defiantly at her and kicked up a splash of water with his foot, though it was impeded somewhat by his wet clothes and shoes. "Looks like it didn't work, Denman."
"Put him on the boat," she ordered. "Somewhere secure we can keep an eye on him."
"No!" Cleo screamed, reaching fruitlessly for Lewis as the two men pulled him roughly from the water and dragged him away. She turned furious eyes onto Dr. Denman. Her fingers imitated claws as she tried to draw a pillar of water from the pool.
Her face fell as many moments went by with nothing accomplished.
"Do you think I'm that stupid?" Denman sneered. "I've done my research, Cleo. Tonight is special. The moon took your powers. You can't hurt me."
Emma put a steadying hand on Cleo's shoulder and Rikki shared a frightened look with her.
"Unfortunately, the same can't be said about you, girls."
The brawn of the operation materialised suddenly without Lewis.
"Now!" Denman announced eagerly. "Which one of you is going to be first?"