Fire alarms began to blare, a piercing sound echoing through the undersea complex. Jeremy watched with satisfaction; his Charmeleon had done a fine job and, judging by the way the fire lizard was posing, he knew it. With a bit of luck, this should keep Team Midnight busy long enough for the group of friends to do what they had to do.

"C'mon, Jeremy!" called Kelly, who was watching from a short distance away. "We need to get going!"

Jeremy looked at his sister and nodded his agreement. He pulled out Charmeleon's Poke Ball and pointed it at the Pokemon. "Charmeleon, return!" he ordered, watching as Charmeleon disappeared in a flash of red light. Then, he pocketed the Ball and hurried to join the others. "Let's go!"

"OK," said Autumn, turning to her Pikachu. "Now, you know what to do if we run into any Team Midnight agents, don't you?"

"Pika!" replied Pikachu, his cheeks sparking in anticipation.

"You too, Elekid," added Ryan. The nine-year-old boy was extremely proud to be part of this; it seemed like an adventure to him. On many occassions, he had daydreamed about fighting bad guys like in his comics, striking a blow for justice with his trusty Elekid at his side. In these fantasies, he had called himself the Elekid Kid and, back in Cherrygrove City, had even gone as far as writing a story about his exploits. Unfortunately, he used Candida's computer to write it and, less than pleased at finding it cluttered with his "rubbish", she deleted the offending files. Then, she set up a password to keep him from using her computer without permission again.

In any case, Ryan was ready for adventure. And so was Elekid, who jumped up as electricity crackled between the horns on his head. "Elekid kid kid!" he cried, clapping his hands.

Kevin looked at the two Electric Pokemon, his hand briefly straying to his Poke Balls. He thought of Sneasel, Houndour and Murkrow, his loyal Dark Pokemon, and prayed this plan would work. If it didn't, he would never again be able to release his Pokemon without fear of them turning on himself and his friends. "OK, let's do it!"

Meanwhile, Marc's Squirtle was swimming around in the ocean outside Aquarius. His mission was, he knew, of supreme importance - he had to get rid of the object tucked inside his shell. That object was a fragment of the Rock of Darkness, the thing which Team Midnight sought and which had been used to control Kevin. The only problem was Squirtle didn't know Dig; Marc had never taught him that move. So how was he supposed to bury the fragment?

He thought for a moment - maybe he could still dig a hole, even if he didn't know the Dig Attack. So he set to work, scraping at the ocean floor with his claws in an attempt to gouge out a hole. But the job seemed to take a long time and his arms soon began to ache as he struggled to keep going, telling himself that he was doing this for his trainer and his friends. Soon, however, he found that he could not continue. He had done his best, but, lacking the Dig Attack, he could not pull this off.

Squirtle sat down on the ocean floor and sighed, dreading the thought of returning to Aquarius with the news that his mission had failed. If only there was a Pokemon who could help . . . What he needed was a Water Type that could learn Dig, but there were precious few species that met those criteria and not many of those that did were deep ocean-dwellers.

Just then, a pretty pink Corsola swam up to him. "Corsola corsola?" she asked him in her singsong voice. It was unusual to find a Squirtle at the bottom of the ocean; they usually preferred fresh water, although a few members of their evolutionary line did live in the ocean. But there were none in the Olivine Sea and she was curious to know what this one was doing here.

"Squirtle," replied Squirtle, retrieving the fragment from inside his shell. "Squirtle squirtle squirtle. Squirtle squirtle squirtle squirt?" He was telling the Corsola about the mission Marc had sent him on, before asking her if she knew Dig. The fragment had to be buried as quickly as possible and only a Pokemon that knew Dig could do it.

"Corsola!" Corsola jumped up and down, her way of saying "yes."

"Squirtle!" Squirtle sighed, relieved. He walked over to Corsola and placed the fragment of the Rock of Darkness on her body, balancing it between the two horns. "Squirtle squirtle!" he urged.

"Corsola!" Corsola smiled at Squirtle and began to rapidly burrow under the sea bed, digging so fast that she had disappeared from sight within seconds. And, seconds after that, she broke through a short distance from where she had started her undersea tunnel, a triumphant grin on her face. This time, there was nothing balanced between her horns. "Corsola corsola," she told Squirtle, letting him know that she had done what he wanted her to.

"Squirtle," said Squirtle. "Squirtle squirt. Squirtle." He was thanking her, then telling her that he had to go; his human friends needed him. With that, he turned round and began to swim away, heading back to Aquarius.

"Corsola!" Corsola called after him. In response, he turned to see her standing on the seabed, her front "limbs" raised. It was her kind's way of acknowledging a departure, the equivelent of waving goodbye, but it was rarely used for other Pokemon species. To be shown this gesture was a special privilege, a sign that the Pokemon concerned had done something to earn the Corsola's favour. And this particular Corsola had heard many rumours about the Rock of Darkness and how it could turn Dark Type Pokemon into evil monsters bent on destruction. In the last couple of days, many a Carvanha, Sharpedo and Crawdaunt had been sighted with glowing red eyes, a sure sign that the Rock of Darkness was controlling them. Carvanhas and Sharpedos could be quite vicious anyway, but the Rock seemed to enhance their natural tendencies and even the normally mild-mannered Crawdaunts could do some serious damage with their pincers. The Water/Dark Pokemon had to be brought under control before it was too late . . .

As she and her friends ran in the direction of Rich's office, Candida suddenly heard something. But what could it be? She paused to listen; it sounded like . . . human voices. Were there Team Midnight agents lurking nearby? Probably, she thought, since no-one else was around. But how many were there? She pulled out her Togetic's Poke Ball and made ready to activate it if necessary.

"Who's there?" she called with more confidence than she felt. "I'm warning you - I've got a Pokemon that knows Hyper Beam! And I'm not afraid to use it!"

"What's wrong, Candy?" asked Ryan as he drew level with his sister. His Elekid was directly behind him, with Autumn alongside, her Pikachu on her shoulder. Marc, Jeremy and Sandra were in front, while Kevin and Kelly were bringing up the rear. So far, they had been lucky and hadn't run into trouble, but how long could that last?

"Did you guys just hear something?" Candida addressed the whole group.

"Now that you mention it," replied Autumn, "I did."

"So did I," added Sandra. "It was coming from one of the locked rooms down this corridor."

"Team Midnight agents?" was Candida's next question. She had meant what she said when she threatened to have Togetic use Hyper Beam on the unknown speakers. The Flying Pokemon might look small and dainty, but she could be an extremely brave fighter; Candida knew this from personal experience. She would have preferred to have her big powerful Lapras, but Lapras weren't much good at battling on dry land. Besides, Togetic was . . .

"I doubt it," said Kevin, his words cutting into Candida's thoughts. "I mean, Team Midnight are a bunch of crackpots, but even they don't go round locking up their own agents."

"Well, then who?" This question came from Autumn, who was as puzzled as everyone regarding this latest mystery. Since Team Midnight took over Aquarius, they had been able to roam the facility with impunity, while the bona fide residents slaved in the undersea mine. As far as the youngsters were aware, they were the only ones who had managed to escape.

"That's what I aim to find out." With that, Kevin hurried back down the corridor, with his friends following in his wake.

They found him standing by one of the locked doors, his hand on one of his Poke Balls. "Kevin!" Kelly shouted the second she saw him. "What are you doing?!"

"What's it look like? I'm gonna have Houndour burn through that door."

"No!" Kelly jumped at him and snatched the Poke Ball out of his hand. "I can't let you, not with the Rock of Darkness still around!"

"She's right," agreed Jeremy, backing his sister up without realising it. Usually, the two siblings argued about the slightest thing, but that hadn't happened lately. In fact, it was as if this crisis with Team Midnight and the Rock of Darkness had brought them closer together. "There's no telling what will happen. Besides, I've got a Charmeleon. Remember?"

Kevin looked at his friends, an apologetic expression on his face. He had briefly forgotten about the Rock of Darkness. Marc's Squirtle was outside disposing of the fragment he, Kevin, had been forced to where round his neck, but the Rock itself was still in Aquarius. And the others had warned him not to let any of his Pokemon out until this was over and the Rock was removed. He wished he could help, but, as a trainer of Dark Type Pokemon, there was little he could do here.

He sighed reluctantly. "OK. Jeremy, call Charmeleon."

Jeremy did so and his red fire lizard soon stood in the corridor, the flame on the tip of his tail burning brightly. "Charmeleon, Flamethrower!" called Jeremy. "Burn through the lock on this door - and hurry!" His heart was pounding madly (as were those of his friends). At any second, Team Midnight would find out that the fire alarm had been a diversion and the agents would come hurrying back. And, if the youngsters were still here when that happened . . .

"Char!" Charmeleon threw back his head, cranked his fire power up a notch and breathed a hot jet of fire at the door, aiming at the lock. It was a similar trick to the one the boys had tried before, when they wanted to see what was in those areas of Aquarius that had been placed off limits. Back then, it had seemed like a game, but now it felt as if the very future of the world lay in their hands. Jeremy and the others kept close watch on Charmeleon. He was doing his best, but the lock had hardly melted at all and there was no Houndour to help him out. Still Charmeleon used his Flamethrower on the lock, confident that it would only take a few more seconds to burn through. But, then, Candida spotted something.

"Jeremy!" she called, pointing to Charmeleon.

Everyone turned in Charmeleon's direction. He was breathing heavily, with puffs of smoke coming out of his nostrils. And the flame on his tail had gone down considerably, almost to a faint flicker.

"It must have used up too much energy," said Sandra, looking at the Charmeleon. Every few seconds, he would try to produce at least some fire, but he was only succeeding in producing a lot of smoke. And Sandra, although she wasn't an expert on Fire Pokemon, knew a Charmeleon's tail flame going out was extremely serious. For members of the Charmander line, the flame on their tails was their source of energy, their lifeforce. And, if the flame started to go down, it was important to rekindle it as soon as possible - before it went out altogether. If that happened, the Charmander, Charmeleon or Charizard was doomed.

"Quick, Jeremy!" urged Candida. "Call it back before its flame goes out!" She had just thought the same thing as Sandra.

Reluctantly, Jeremy raised his Poke Ball. "Charmeleon, return!" he called, watching as Charmeleon disappeared in a flash of red light. "Now what do we do?" he demanded, looking first at his friends, then at the scorched door. Charmeleon had done at least some damage, but it didn't look as though it had been enough to open the door.

"Don't look at me," said Autumn. "I don't have the answer either." She sighed deeply. They were in a fix and no mistake. Charmeleon had been unable to burn through the door and the only other Fire Pokemon they had was Houndour, who would surely turn on them the second he was released. And, yet, she knew there had to be some way to get that door open. But how? Autumn sat down and buried her face in her hands, feeling extremely frustrated.

Then she felt a tap on her back and turned to see who it was. Her Pikachu was standing there, a thoughtful expression on his face. "Pika pika!" he told her, pointing to the door.

Autumn guessed what he was trying to say. "You want to try an Electric Attack?"

"Pika pikachu!" Pikachu cried, pointing at Ryan's Elekid.

And you want Elekid to try too?"

"Pika!" Pikachu nodded vigorously, sparks already flying from his cheeks.

The friends all saw the sense in this; having two Pokemon team up to try and break the door down was much better than one Pokemon trying to do it alone. Hopefully, with their combined power, Elekid and Pikachu would be able to produce a Thunderbolt powerful enough to take that door out. Candida turned to her brother. "OK, Ryan," she said. "Go right ahead."

Pikachu and Elekid stood side by side. Sparks were flying from Pikachu's cheeks and the tips of Elekid's ears as both Pokemon charged up ready to unleash their Electric powers. Most of the youngsters stood well back, out of range of any stray sparks, as Autumn and Ryan prepared to give the command to "use Thunderbolt."

"Pikachu!" called Autumn.

"Elekid!" Ryan called a fraction of a second later.

"Thunderbolt!" both youngsters said in the same instant.

And Pikachu and Elekid let fly with a double blast of electricity, striking the lock dead on and frying it in an instant. Clearly, Charmeleon's Flamethrower had done some good, even though he hadn't actually succeeded in getting the door open - Pikachu and Elekid had simply finished what he started. And, thanks to the way all doors within Aquarius had been designed to spring open if the locks failed, the door was open immediately and the youngsters were soon peering at what lay beyond . . .

Cells. An entire corridor of cells, all of which were apparently unguarded, had been hidden behind the door. "Looks like Team Midnight slipped up on their security arrangements," remarked Sandra as she peered down the corridor.

"But we'd best be prepared," said Kelly. She let Pinky, Cheeky and Delibird out and nodded to her friends. "Those of you who can, let out a Pokemon."

In response, Candida let out Togetic, while Sandra let out Wooper and Dratini. Autumn's Pikachu and Ryan's Elekid stood proudly beside their trainers. Kevin, Jeremy and Marc did not release any Pokemon. Kevin's Dark Types were still at risk from the Rock of Darkness, Jeremy's Charmeleon was weakened and Marc only had his Seadra with him. Squirtle was still outside Aquarius, but was hopefully on his way back.

Stealing themselves and keeping constantly on the alert for approaching Team Midnight agents, the youngsters and their Pokemon entered the corridor, breathing a collective sigh of relief when they didn't trigger any booby traps. Then, they glanced at the nearest cell and saw who Team Midnight's prisoners were.