On the island the crew of both the expedition ship and the Gun Fort V3 were gathered on the shore. While the expedition ship crew set up their equipment, the crew of the GUN Fort V3 were accosting Topaz.
"If you'd have put up a fight against Eggman instead of letting him capture you, we wouldn't be stuck here." GUN Pilot said.
"Yeah. We had Eggman trapped, but he had you and your crew on board, so we couldn't destroy his ship." GUN Gunner said.
"Don't act like that's what stopped you!" Topaz said and fan off.
"She's upset." Tanaka said.
"Why don't you go and comfort her?" Chuck asked.
Tanaka bowed.
"If you insist, sir. I will do what I can." he said and ran in the direction Topaz went in, and soon met her on the beach.
Tanaka blushed.
"Those two bullies..." he said to himself.
In a show of strength to impress Topaz, Tanaka karate-kicked a rock and punched another, but his hand started to swell.
Back with Chris and the others.
"But I know I could fly the X-Tornado down into the crater." Tails said.
"It's too dangerous!" Chris said.
"It's the only way to catch up with Eggman. I'm in." Sonic said.
"Rouge, what about you? You willing to come along?" Knuckles asked Rouge.
"Doesn't sound like I have a choice. If I stay behind, there won't be anybody left on the team to look after you." Rouge said.
"Ha. Very funny."
He knew Rouge still wasn't happy after finding out he's dating Sonia.
Meanwhile, Tanaka and Topaz returned to Chuck and Dr. Cadberry.
"We have found something. Here, doctor." Tanaka said and handed Dr. Cadberry a shiny metal box of some sort.
"Incredible! This bot seems to be made of ermurasium." Dr. Cadberry said.
"What's ermurasium?" Chuck asked.
"It was an unusual metal that was used by the Murasians." he said and opened the harahirecon box.
Inside was a beautiful white gemstone. Immediately Rouge's eyes sparkle.
"Hel-lo..." she said.
"According to my research, Murasian cities were filled with precious gemstones even larger than this one." he said and held up the gem. "Amazing..."
"I never knew archaeology could be so fascinating."
On the volcano the Eggmobile was descending the crater of the volcano.
"Doctor, we will hit the lava soon." Boccoe said.
"Heheheh... I have a plan; don't worry." Eggman said.
Decoe rolled eyes.
"If it is anything like his past plans, we are going to get burned." he said then Bokkun popped up between them.
"Are you two doubting Dr. Eggman?" Bokkun asked. "Doctor! Doctor! They're dissing you!" he shouted out.
Decoe and Bocoe narrowed their eyes.
"Know what I like about him?" Decoe asked.
"Yes. Nothing." Bocoe said.
Bokkun scowled before flying into a rage.
"Well I don't like you two either!" he said.
Eggman tapped several buttons.
"I've located a tunnel that'll take us further underground." he said.
Then the treads extended out of the sides of the Eggmobile. It landed, and they moved along the ground.
On the ialand Tails and Chris were seated in the X-Cyclone and Sonic, Knuckles, and Rouge were standing on the wings.
"Let's go check out that volcano." Tails said then the X-Cyclone took off, and flew toward the crater of the volcano and slowly started to descend it.
Soon the X-Cyclone landed on the volcano and left the craft. Rouge examined several rocks nearby.
"They've blocked up the tunnel after they drove through. You see?" she said.
"Hmph. That won't stop me!" Sonic said excited and immediately started burrowing through the rock with a spin-dash.
"If you don't stop that digging, you're gonna bury us here!" Knuckles said so Sonic stopped.
"Heheh, sorry."
Rouge investigated a tunnel different than the one Sonic created.
"There's another tunnel here, but it's pretty narrow." she said.
"Let's see where it goes." Sonic said.
Rouge entered the tunnel, followed by Sonic and Knuckles.
"What about us?" Chris asked.
"We can look around in the X-Tornado." Tails said and Chris nodded.
A few minutes later Rouge, Sonic, and Knuckles were in the tunnel in total darkness and Rouge stubbed her foot on a rock.
"Careful! You both have big heads. Good thing they're hard." Rouge said.
Knuckles growled.
Then the walls started glowing with many soft green lights.
"It's some kind of fluorescent moss." he said.
"How'd you know that?"
"Easy. When you're a treasure hunter like me, you've been everywhere, you've seen all kinds of-"
"Come on, Sonic."
"I see! It's two against one now!" Knuckles said and chased after them.
Soon they were carefully descending a vertical shaft - Knuckles first, then Sonic, then Rouge.
"These rocks are really slippery. Watch your step." Knuckles said.
Then Rouge slipped on the moss and landed on Sonic, who landed on Knuckles, and the all landed in a heap at the bottom.
"Oopsie." she said.
"I'm always the fall guy." Knuckles said.
Then they continued across a plateau. They crossed a dangerous bridge over a river of lava. Soon they came across a stream.
"It's... so wet!" Sonic said wary.
Knuckles emerged from the stream.
"It's too deep to wade across. We'll have to swim." he said.
"But... That'd spoil my makeup." Rouge said.
Anger was sparked within Knuckles while Sonic rolled his eyes.
"You can rot in this cave for all I care, but you're coming with me!" Knuckles said and he and Sonic went into the water.
"Maybe I should go and keep Chris and Tails company." he said but before he could leave, Knuckles wrapped his arm around his shoulder.
"Hey, not so fast! The bat can rot in this cave for all I care, but you're coming with me!" he said and dragged him into the water.
"Ya can't get rid of me that easy!" Rouge said mad.
She dove in after them, and they wade through the water. Soon, they reached the other side of the stream, and Sonic is on the ground panting and coughing.
"What a nightmare." Sonic said.
"I hear a waterfall." Rouge said and Sonic immediately leapt up.
"It might be a way out!" he said and ran over to the nearby waterfall and looked down.
There were rocks at intervals in the waterfall. The others joined him, and saw that the waterfall went down into utter darkness.
"Looks like a dead end." Knuckles said.
Suddenly Rouge took off.
"Hey, wait!" he said as she dropped crushing Knuckles.
"You OK?" Sonic asked and Knuckles nodded.
"Thanks, Rouge!" Sonic said and started climbing the vine.
"I'll get that bat..." Knuckles said and climbed the vine and joined the others at the top of an overhang.
Rouge pointed to the wall behind her. It was blocked off with vines and rocks.
"Our exit's blocked off." she said.
"No sweat. I'll just dig us out." Knuckles said and held up a Shovel Claws, and started burrowing through the rocks.
Rouge and Sonic shielded themselves.
Having finished digging, a bright light poured through a crack. Sonic spun through it, and saw amazed at that he saw.
"No way!" he said.
It was an ancient ruins of some sort. The X-Tornado flew overhead.
"Murasia!" Tails and Chris said as the X-Tornado projected a camera out of its tip.
Meanwhile Chuck, Tanaka, Topaz, and Dr. Cadberry were watching the live feed the X-Tornado was projecting.
"The Murasians built an underground kingdom." Dr. Cadberry said.
"But how?" Chuck asked.
"As their continent sank, they must have fled to this huge cave and used the power of ermurasium to make an artificial sun to provide heat and light." he said. "Once the Murasians moved underground, some legends say they encountered terrible creatures who destroyed their kingdom and drove all the survivors away. I always thought the stories of underground kingdoms and monsters were myths, but it seems there was some truth to them after all."
Meanwhile Sonic, Knuckles, and Rouge were once again riding the X-Tornado.
"I don't believe those monster stories." Rouge said.
"I'd love to meet monsters down here. I could challenge 'em to a fight! I'd destroy 'em all!" Knuckles said.
"You know, you're kinda cute when you talk about how tough you are."
"You know I can't stand you?"
"I'm not surprised. There's a very thin line between hate and love."
"Well, you make it thicker!"
"Could you two take it easy, please? I've got enough turbulence up here." Tails said.
Sonic had trouble not laughing remembering the first time Sonia and Knuckles met and she kissed him.
"Athair, we brought you the Chaos Emerald for safekeeping." Knuckles said.
"The Emerald must be kept by you. On the floating island." Athair said.
"But you'll be coming with us won't you, to join the resistance?" Sonia asked.
"Knuckles' duty lies on the floating island. Just as your duty lies with the resistance."
"And finding mom!" he said.
"But if you ever need a break from fighting Buttnik, there's always room on the floating island." Knuckles said.
"And you're welcome to sit in with a Band anytime!" Sonia said and kissed Knuckles.
Knuckles sat there thinking about the same thing.
'I'll see you again someday Sonia.' he thought.
Sonic felt a little bad for him but knew he wasn't going to leave him.
So he looked at him and put his hand on Knuckles' shoulder getting his attention.
"You'll see her someday. I promise." Sonic said and Knuckles smiled and nodded.
Back with Chuck, Tanaka, Topaz and Dr. Codberry.
Chuck scratched head.
"Those two are like oil and vinegar." he said.
Topaz and Tanaka looked at each other and smile.
Back at the Island Eggman had set up a tent, and was typing on a laptop. Suddenly Bokkun popped up and bang a fork against a plate.
"Hey, I need to put something yummy in my tummy!" he said.
"Now that you mention it, I'm hungry too. Decoe, Bocoe, go grab us some grub on the double!" Eggman said.
Then Decoe and Bocoe appeared in the tent entry.
"But what if we get lost, Doctor?" Decoe asked.
"Ha! I'm not that lucky!" Eggman said.
"Why don't you send Bokkun?" Bocoe asked.
"There might be wild animals around here. I don't wanna be a snack for a snake!" Bokkun said.
"Bokkun's right. You two are indigestible." Eggman said as he sat back and waved his hench-bots away.
Then they left.
At a Murasian palace the X-Cyclone has landed in front of a giant Murasian palace and Tails was setting up a small device.
"Cross your fingers." he said and pressed a button on the device.
With the expedition crew paper fed out of the machine that had been set up.
"The seismograph seems to be working fine." Chuck said.
"The seismic readings will give us an idea how much internal pressure is building up inside the volcano." Dr. Cadberry said.
Meanwhile Deoce and Bocoe were foraging for food.
"This is hopeless." Decoe said.
"Look! I found something!" Bocoe said and held up a large slug, causing Decoe to freak out.
"Is it edible?!" Decoe asked.
"It probably tastes like chicken."
"I do not want to find out." he said and Bocoe tossed the slug away. "There! That looks more appetizing!"
There is a large fruit on a tree nearby. The two robots approach it.
"I have never seen such a huge cherry." Bocoe said.
"Our search has been very fruitful." Decoe said and climbed onto Bocoe's shoulders and prepared to pick the apple… except it wasn't an apple.
Instead, it's the antenna of a giant moth named Mothmacin. They fled as Mothmacium flew after them.
Back at the Murasian palace the group looked up to see the screaming robots.
"Eggman's robots!" Sonic said.
The group cried out in fear as they saw Mothmacin flying over them in hot pursuit of the robots.
"Maybe we should do something to help them!" Chris said.
"This monster is bugging me out!" Decoe said.
"Right now I would give anything for a giant mothball!" Bocoe said.
"Maybe I could distract that thing." Chris said and threw a stone at Mothmacin.
It strikes the giant moth in the eye. Chris begins running after Decoe and Bocoe as Mothmacin chases the three of them. Its flapping wings kick up dust, blowing the trio to the ground. They fall through a deep hole in the grass.
Meanwhile Sonic, Knuckles, and Rouge were searching for them.
"Hey Chris!" Sonic said and looked around. "Where could he be?" he said to himself.
Meanwhile Chris, Decoe, and Bocoe finished falling through the hole. They landed right behind Eggman, who turned around.
"What did you bring that brat here for?" Eggman asked and they sat up.
"He risked his like to save us from a giant bug." Decoe said.
"Really? Well, he isn't gonna save you from me when I tear out your power supply!"
Suddenly the ground started shaking. Decoe and Bocoe ran around Chris in a panic.
"The gate is going to collapse!" Decoe said.
The expedition team members also feel the ground shaking.
"I hope everything's all right in the cave." Amy said then a seismograph recorded the earthquake. "Are Sonic and the others gonna be okay?"
"That was just a tremor, so they should all be fine. But the pressure inside the volcano is building. Your friends are going to be in real danger if they stay down there much longer." Dr. Cadberry said.
"How bad are things going to get, Doctor?" Chuck asked.
Dr. Cadberry pointed to the seismograph.
"The data suggests the volcano is about to erupt." he said surprising the others.
Meanwhile the X-Tornado had landed. Tails was still inside. Dr. Cadberry's message was broadcast to the X-Tornado.
"If you're still down there when the volcano blows, you'll be in great danger. Forget about Eggman. Just pack up your gear and head for the surface right away!" he said.
"Okay, Doc." Tails said.
"What do we do?" Knuckles asked.
"We don't have any time to lose. I gotta find Chris fast!" Sonic said and ran off.
"We should come up with a plan first!"
"The best thing for me to do is wing it." Rouge said and took off into the air.
"Where do you think you're goin'?"
"I'll search for Chris from the sky. You and Tails can set up the equipment and look for that hot spot. Make sure you find it before Eggman blows it up."
"All right, but be careful, Rouge. Good luck."
"I'll see you soon, handsome." she said and winked and flies away.
At Eggman's camp Chris was sitting on the grass, tied up. Decoe and Bocoe were standing behind him then Eggman walked up to them.
"For such a small fry, you certainly are a big sap. You risked your neck to save these clowns and now you're my prisoner! How hilariously humiliating!" Eggman said and laughed.
"I'm glad I tried to help them." Chris said.
Then another earthquake ravaged the island. A pair of what looked like purple eyes appeared in one of the caverns. Eggman looks at his tablet.
"My analysis is finally finished, and it shows the hot spot is only a few hundred yards away." Eggman said.
Decoe and Bocoe were cowering underneath the transformed Eggmobile. Eggman kicked them aside.
"Quit loafing and let's get moving!" he said.
Back with Tails Knuckles watched Tails as he set up another device.
As Sonic searched for Chris in a forest, Rouge searched for him in the air. A glittering object near the ruins caught her eye. She swooped down to investigate, and it didn't take long for her to find the source of the shine.
"Oh my..." she said.
A treasure trove of gemstones was right within her reach. As she approached, one gem fell loose from the pile.
Back with Eggman Eggman landed the Eggmobile at part of the ruins. He stepped forward, followed by Chris, still tied up and escorted by Eggman's hench-bots.
"Do you have the detonator?" Eggman asked.
"Yes." Bocoe said.
"Watch closely, kid. You'll see why I'm called a master of mayhem! By setting off a blast in this spot, I'll cause a chain reaction! This whole planet's gonna blow its top!" he said tro Chris.
Then a shot of an erupting volcano was shown.
"Every volcano in the world will erupt, leading to worldwide chaos! On top of the ashes of the old world, I can build my new Eggman Empire!" he said and laughed.
"Sonic'll stop you in time." Chris said.
"He'd better hurry, 'cause I'm gonna hit the detonator switch right now!"
"Here." Bocoe said and handed the detonator to Eggman.
"You can't set that off!" Chris said.
"Just watch me!" Eggman said.
Even with his hands bound, he moved toward Eggman to try to retrieve the detonator.
Then he lifted the detonator out of the way, causing Chris to stumble and fall headfirst onto a rock.
"Sorry about that, Chris." Bocoe said.
"Dr. Eggman, that was mean!" Decoe said.
"That klutzy kid gave himself the slip." Eggman said dismissive.
On the volcano Bokkun was sitting atop a dinosaur statue.
"This dinosaur rocks!" he said.
Suddenly the ground shook again, and the statue tilted.
"Not another quake!" he said and clung to the statue as the quake caused the statue to form a large vertical crack.
Then the statue broke apart, causing Bokkun to fall. In his place, a giant robot named Mongroun rose.
Meanwhile Rouge was holding one of the gems.
Then someone screamed.
Bokkun was running in a panic. He met up with Eggman's party. Decoe and Bocoe were just finishing untying Chris.
Ihen he ncoherently explained the situation, Eggman rubbed his head. Suddenly the ground shook, and the group found themselves overshadowed by the humongous Mongroun. Everyone was freaked out at the ancient robot's size. Mongroun raised its giant drill hands.
"SONIC!" Chris yelled.
Sonic heard his call.
Just as Mongroun appeared to swing, causing Chris to shield his head, Rouge swooped down and picked him up.
"Need a lift?" she asked.
"Thanks, Rouge." Chris said.
Mongroun started destroying the building and Eggman and Bokkun fled. Decoe and Bocoe looked at the timer on the bomb with 10:30 remains.
"The detonator!" Bocoe said.
"Oh no!" Decoe said and they fled while Mongroun flailed about, destroying the building completely. "Hurry! We must rush to avoid the crush!"
They fell on their knees in front of Chris and Rouge and watched Eggman fly away.
"He is gone! We are stranded!" Decoe said.
Suddenly the volcano started to erupt. Smoke and ash left the crater as Mongroun thumped its chest.
"The heat's on now." Rouge said.
"What do you mean?" Chris asked.
"This whole cave's gonna fill up with lava."
Bocoe leapt into Decoe's arms in fright.
Cracks ran down the mountain as Mongroun walked away from it.
"Let's get outta here." she said.
"It is no use. A bomb is gonna cause all the volcanoes on the planet to erupt!" Bocoe said.
Suddenly Chris took off running toward the Murasian palace.
"Hey! Wait!" Decoe called out.
"Where are you going?" Bocoe asked calling out.
As Chris ran, Mongroun detected him and raised its foot to crush him. However, Rouge executed a Screw Kick on Mongroun.
The attack did absolutely nothing. Mongroun rubbed the spot on its head where Rouge struck it.
"Ah!" she said.
The distraction gave Chris enough time to ascend the front stairs of the palace. Mongroun swated Rouge to the ground and walked toward the palace. Meanwhile, Chris found the time bomb. 5:08 remained. Then he saw Mongroun approaching and held out the bomb.
"Come on! I got something for ya!" he said.
Decoe and Bocoe caught up to him.
"Wait, kid!" Bocoe said.
"We will help you!" Decoe said.
"But what can you do?" Chris asked.
"Outside, we look like servants." Bocoe said.
"But inside, we are built for battle. All we do is put our heads together..." Decoe said.
"...and the results are electrifying!"
Chris and Mongroun turned to them.
"What? What are you talking about?" Chris asked.
Decoe and Bocoe started a combination which eventually turned them into a giant robot. It sported Decoe's legs and Bocoe's upper body.
"First we link up." Bocoe said.
"Then our internal circuitry undergoes a total integration." Decoe said.
"Then our transformation sortware is activated."
"Which kicks us into Power Armor Mode!"
"Which creates a mighty mechanical giant!"
"A super colossal combat droid!"
"Well, now's the time to do it." Chris said.
It is revealed that the giant robot transformation never happened.
"Here we go! Bocoe Decoe Battle Mode!" Decoe and Bcoe said.
The two robots linked arms… but nothing happened.
"Huh?" they said.
"We must have been in dream mode." Decoe said as Mongroun became mad. "Hey, look out!" Chris said.
The warning came too late. Mongroun used its tail to swipe the two robots away. They broke apart in the impact.
"Sorry!" Bocoe said.
"It appears our rescue plan has fallen apart!" Decoe said.
"Decoe! Bocoe!" Chris said.
Mongroun rose its arms, but a missile struck it in the chest. The X-Tornado arrived, carrying Sonic and Knuckles.
"There's Chris!" Tails said.
Chris waved his arms.
"Hi, guys!" he said.
Sonic and Knuckles leapt off the X-Tornado to attack.
The X-Tornado blast Mongroun to no effect. Knuckles grabbed the giant robot's tail and swung it around before letting go. Mongroun sat up and breathed fire at Knuckles, who was forced to jump back. Not even a spin attack from Sonic damaged the giant Murasian robot. Knuckles helped Rouge up.
"Rouge, are you okay?" he asked.
The X-Tornado launched a Power Ring to Sonic, who caught it.
The ring-powered Sonic spins toward Mongroun, but the robot bats him to the ground.
"It's pretty tough." Sonic said.
Mongroun breathed fire again, but Sonic scooped up Chris and leapt him to safety. Then they rejoined Knuckles and Rouge.
"There must be a way to stop it." Knuckles said.
"You're right, but I don't know what it is." Sonic said.
Then Chris presented the bomb to him.
"Hey, Sonic. This might help." he said so Sonic took the bomb.
"We can send it off with a bang." he said.
He, Knuckles, and Rouge leapt into the air toward Mongroun. While Rouge flew around the robot to distract it, and Knuckles punched it, Sonic readied his bomb.
"Yoo-hoo!" Rouge said.
"Down the hatch!" Sonic said and dropped the bomb into Mongroun's small mouth.
It exploded seconds later, effectively destroying Mongroun.
"All right!" Chris said.
Then the volcano erupted again, sending lava into the air and giant cracks running through the island.
"Come on! We gotta go!" Tails said.
Later, it was sunset, and everyone was leaving the island in the boat. The volcano was still spewing smoke, but it appeared to be calming down.
"Murasian culture seems more mysterious than ever to me now. I only wish we had more time." Dr. Cadberry said and they continued to watch the volcano. "Their achievements were astounding. But perhaps they went too far. Did their quest for greatness lead to their destruction? We may never know for sure."
Rouge examined a jewel she smuggled off the island.
"Today I almost got crushed in a cave, mangled by a monster, and cooked by a volcano, but finding this baby made it all worthwhile." she said.
Dr. Cadberry takes the gem from Rouge and holds it high.
"Another underground artifact from the underground kingdom of Murasia!" he said and shook her hand. "Thank you, Rouge. Feel free to drop by the museum any time and see it."
"Yeah, sure Doc."
"Decoe and Bocoe sacrificed themselves to help me." Chris said to Sonic.
"Yeah. Guess they weren't so bad after all." Sonic said.
"They proved themselves to be heroes." Tanaka said.
"I'm gonna miss having those two as enemies." Amy said.
Chris could almost see the faded forms of Decoe and Bocoe waving at him.
He had flashbacks of his time with them - when they held him captive... when they were assisting Knuckles with the Master Emerald... when they cried.
Amy, Ella, Topaz, and Tanaka showed sadness for the lost robots.
"You have warmed our cold metallic hearts." someone said.
The cabin door opened and in walk none other than Decoe and Bocoe.
"Luckily, we pulled ourselves together just in time to escape the volcano." Bocoe said.
"You really are incredible." Chris said.
Then Chuck and Tails entered.
"Two resourceful robots like these could come in very handy someday." Chuck said. "If they'd like to join our team." he said to Decoe and Bocoe.
"Oh, you bet we would!" Decoe and Bocoe said.
"Dr. Eggman always works us overtime!" Decoe said.
"We would like to work him over!" Bocoe said then they made their way to the edge of the ship.
"We slaved away for Eggman for long enough!"
"Now we will take charge of our own future!"
"Eggman, we quit!" they shouted out.