A/N: Well I have been thinking about a 20,000 Leagues Under The Sea crossover, but none of the animes I really knew really fit anywhere close to what would be a workable time period. Until I decided upon the world of Avatar, more specifically the Legend of Korra...now this will be obviously a bit AU (ok a bit would be a understatement lol) with stories from characters adapted for the story and such especially the Nautilus. For the story I'll be combining aspects from the book and the 1954 Disney Movie as well for characters too.

Anyway I hope you'll enjoy it and I got some events planned especially with the involvement of Captain Nemo with other characters from the books to make their own appearance.

Chapter 1

Divine Providence

One hundred feet below the ocean surface, somewhere in the South Seas northwest of Whale Tail Island was from stem to stern exactly seventy meters, and its maximum breadth is eight meters. The vessel was double-hulled built from the strongest metals that only its designer and creator was only able to produce. As the metallic vessel cruised through the sea music could be heard from within its hull, near the center of the ship was the salon.

The salon for a vessel such as the one traveling below the ocean surface was exceptionally well furnished compared to most sea-going vessels with a library, a display table containing boxed collections of valuable oceanic specimens that are currently unknown to the outside world, expensive paintings, and several collections of jewels. Adjoined with the salon was a lavish dining room and the first of two prominent features of the salon was an impressive orate organ. The high-pieces of furniture, of black violet ebony inlaid with brass, supported upon their wide shelves a number of books uniformly bound.

Seated before it, playing a haunting, but impressive musical upon the impressive looking instrument as the music being emulated from it echoed throughout the halls of the ship, was a tall reticent man in his early fifties with black hair, with gray hair on the sides, and a full beard, tall with a straight nose and wide-set brown eyes. The organ player was also dressed in a red waist-length robe with a black slash tied around the waist holding it close while the man wore gray pants with black polished shoes and a white cravat to complete his attire.

As the song neared its end a young sixteen year old child entered the room wearing a white turtle neck sweater with blue pants that had a red line going down the side of the leg starting from the hip with black shoes. He had black hair, but he had stern looking green eyes and a fair skin complexion. He quietly approached before stopping near the organ, but the man playing was aware of the young man's presence as he stopped playing to speak with him.

"What is it Jules?"

"Father I thought you should know we are picking up chatter from the surface. I think we have another pirate vessel and right now it's stalking a transport vessel on route to Republic City from the South Pole."

"I see…announce all crewmembers to report to their stations and to prepare to bring the Nautilus up to surface depth." Jules's father ordered as he rose up turning to face him, but by the time he saw his ten year old son the young man was hurrying to the bridge to relay his orders to everyone else. The captain of the vessel made his way to the bridge following after his son before ascending the winding metal stairway leading up to the wheelhouse of the ship.

Waiting on the bridge beside his son were four other members of the crew dressed in blue uniforms with the red lining on the side of their pants as Jules's. One was behind the steering wheel of the ship while another crew member stood next to him handling the dive plane controls. Two other crew members stood at their stations, at the power control for the engines and the other at the Propulsion Switch near the Map Roller.

"Ascend three degrees, slow and maintain distance as we near the surface from the vessels." The Captain spoke as the crew obeyed the order of their captain as the crew member at the dive plane controls adjusted the planes accordingly before another crewmember standing by the power control adjusted the ballast control wheel with the vessel beginning to tilt upward heading towards the surface.

Quietly surfacing with the night sky above them with a full moon provided some illumination over the ocean surface. Jules was standing by his father as the Captain stepped towards the wheel as the crewmember that had been steering the ship stepped aside to allow the captain to take the helm. He looked out at the sea before him seeing the two ships in the distance, but soon signs of a fight between the two vessels broke out.

Looking over his shoulder at his son the Captain spoke, "Go below and secure yourself Jules...I rather not have you up here."

The young man hesitated at first, but Jules ultimately complied with his father's wishes. As he watched his son descend down the spiral stairwell to the lower deck of the ship the Captain was adrift in memories for a moment as he recalled a brighter moment in his life from many years ago.

(30 years ago)

On the outskirts of a seaside town an academy built on the cliff overlooking the sea. It was mid day as a young man with black hair and brown eyes with a fair skin complexion was looking out at the ocean dressed in light green school uniform. He was memorized by the sea, so much so that he didn't heard footsteps approaching from behind as someone closed his eyes suddenly.

"Come on Lin we're twenty years old," The black haired man mused with a smile. Behind him a young and beautiful black haired woman with sharp green eyes removed her hands. She was wearing similar school uniform like her friend.

"Sorry, but it's too much fun." Lin Beifong replied with a laugh.

"There you two are," A new voice called out as the two turned their heads to see another man about their age yet a year older with a bald head and blue eyes, who of course was wearing similar uniform to theirs. "It is time for the graduation ceremony, so hurry up you two."

"Alright Tenzin, but you should lighten up a little. Come on Dakkar," Lin called as Dakkar followed.

"Captain," A crew member asked as the Captain returned to present day as he fixed his eyes once more on the two ships in the distance.

"Which one is the pirate vessel," The Captain asked. A lifetime ago he was Dakkar of the Southern Water Tribe, but now he was Captain Nemo.

"The smaller vessel we have confirmed a pirate flag, the ship belongs to the Sea Devils," The crewmember reported passing the spyglass to Captain Nemo allowing the fifty year old man to observe the two ships ahead. Despite the darkness the lights from the ships combined with the fight happening between them illuminated the area enough at the right moments for the Captain to see a blood red flag with a skull and devil horns upon it.

Putting the spyglass away Captain Nemo gripped the wheel as he commanded, "Stand by engines," Nemo began as the men carried out his orders with the ship's engines starting up once more. "Half ahead," The ship began moving as the hum of the engines could be heard as the Captain steered the ship until he had a clear path aimed directly at the pirate ship as it was exchanging fire with the cargo ship.

Like a silent killer the ship advanced upon the pirate ship, but suddenly a huge explosion from the cargo ship caused a momentarily look of surprise to appear on the captain's face as he watched the cargo ship beginning to rapidly sink below the waves. A surge of anger arose within him as his grip tightened around the wheel, but his expression was calm and stern…yet the evidence of his building anger at the terrible act was clear in his brown eyes.

"COLLISION SPEED FULL!" Captain Nemo commanded as his voice was heard through the speaking tube clear to the engine room where a crewmember turned a control level replying.

"Collision speed full!"

The ship rapidly accelerated as the sound of the engine had become louder giving the sound of some terrible creature from myth as the vessel was speeding towards the pirate ship as the vile crew aboard the eighty year old Fire Nation navy vessel was too occupied with their victory to realize the danger they were in. The water was rushing pass the wheelhouse and over the metal arc that linked with the top front of the wheelhouse down the front of the ship to the ramming plow granting the ship a more menacing appearance as the lights within the wheelhouse appeared to be eyes behind the layer of water rushing pass the viewing ports.

The hum of the engines grew louder as the ship moved faster towards the pirate ship about to ram it head on.

Near the pirate ship a lone survivor from the cargo ship, despite odds had managed to survive. Well as far as human survivors went she was the only one, but there was technically another. A polar bear dog poked its head above the surface as it found a large chunk of wood to grab onto while the young woman was glaring at the ship ahead of her planning on retaliating, but to the distance the humming sound of the speeding submarine boat drew her attention.

The bright lights that looked like eyes just under the surface of the water was heading straight for the bow of the pirate ship with no signs of slowing down.

At this point the pirates finally realized the danger coming straight at them as the helmsman in obvious panic began turning the ship hard to port, but it only gave the oncoming sea monster a clean shot at the Starboard side. Using Waterbending the young woman quickly pushed herself and her polar bear dog companion away from the pirate ship. The monster hit the hull head on as the monster went straight through it not even slowing down.

The monster kept going while a monstrous explosion caused by a combination of an internal explosion from the engine room mixed with the explosive jelly the pirates had on board blew the ship killing all onboard as the bellowing smoking carcass of the pirate ship quickly vanished below the surface. The woman was in shock at what happened. One minutes pirates vicious attacked the vessel before explosive jelly bombs hurled at the vessel sunk it giving her very little time to act and then after that a monster of some kind sinks the Pirate Ship.

"Naga…maybe I should have stayed in the South Pole." Korra commented as she tried to cling to the piece of debris that kept them afloat. As they drifted helplessly with the tide carrying them with only the moon and the stars above them as the only light source while the rest of the ocean around them was dark and foreboding. A eerie calm had settled around them, but for once the young woman who had ran away from the White Lotus Compound at the South Pole was regretting her actions somewhat.

But nothing compared to being unable to prevent the loss of the cargo ship and its crew, which was why Korra almost felt no pity for the pirates who had met their demise not too long ago by the mysterious sea monster. As she thought about it Korra did remember hearing the rumors and tall tales of a powerful sea monster that had been terrorizing the south seas of the world sinking pirate ships, slave traders, and ships carrying illegal goods and such.

Yet never once was there a report of civilian vessels coming under attack from the reported devil of the sea that claimed hundreds of ships in the last fifteen years. As a result some dismissed claims of such a sea monster existing as some tall tale pirates or other criminals who operated on the oceans to cover up double crossings and such.

But now Korra had seen the monster with her own eyes and was now among the very small few people alive to have seen it and lived.

"It's like some of the rumors claimed, glowing eyes and a loud humming sound as it approaches moving faster than any known large sea creature," Korra said speaking to Naga.

For the past eight hours the two were helpless with nowhere to really go and at the mercy of the tides, but as the morning sun rose up from below the horizon a fog bank had set in. Weak and tired as she felt her body becoming numb despite using firebending to keep herself from freezing to death the young Avatar in training saw something…a shadowy visage in the fog.

What is that? Is it Land?

Calling upon what strength remained in her limbs the young Avatar made her way through the fog to the faint shadow she saw, but as she got closer the fog lessened and before her was a metal construct unlike anything she had seen before. She almost could believe her eyes, but undaunted she moved closer until she could touch the metal plating of the vessel before her.

"Naga, are you seeing this? A submarine, but," Korra began as she almost couldn't believe it. She remembered hearing about the submarines created during the last days of the one hundred year war which were powered by waterbending, but since then no one else had managed to create working submarine that was more self-sufficient in the sense it could travel on its own power without the need of Waterbenders and remain underwater for extended periods of time unlike the one hour time limit for the submarines used on the Invasion of the Fire Nation capital.

Korra kept touching the armored plating surface of the ship as Naga carefully climbed onto the deck finally finding a place to rest after being in the water for so long. Resting on the metal deck for a few minutes Korra was breathing hard from exhaustion, but slowly strength was returning to her. Standing once again Korra made her way towards what was obviously the bow of the ship while Naga remained near the stern of the ship resting near a hatch that was underneath the Dorsal Fin of the ship.

The young Avatar found an entrance into the bowls of the ship, but so far she saw no one.

Cautiously the young woman descended into the ship, which to her surprise the interior was as bright as day inside. The interior was unlike anything she had seen on a ship, but the room Korra had entered into was the chart and navigation room where on the right side of the wall was a pair of large maps contained behind a glass sheet while to her left were holding shots for rolled up maps and charts needed for navigation while the room before her had other instruments needed for navigation and on the ceiling some pipes could be seen with a meter-like device labeled reserve air was visible while on the walls to her right near the charts were display dials and meters mounted onto the walls.

Korra stopped at the hand railing at the bottom of the stairs looking over the room before going right to proceed down the second set of steps as she began poking around. She was hesitant to call out to anyone, but even so the ship seemed deserted yet something inside her told her to keep quiet as the young Avatar continued her exploration seeing an open door that went under the stairwell of which she had entered the ship from leading deeper into the ship.

Passing through a short hallway Korra entered the Nautilus's salon which was well lit thanks to its electric lightning. The young woman was surprised by the décor of the room as its priceless works of arts and collections of specimens as well as the organ that could be seen on the opposite side of the salon were certainly eye catching.

But yet there was still no sign of anyone aboard.

"Uh, hello," Korra called out hesitantly, but there was no response so Korra proceeded inside carefully.

After stopping to look at the small water fountain near the entrance Korra saw the circular window on the starboard side of the ship was open allowing her to look out into the open ocean before her. But while looking around for any sign of the crew she did not notice someone sneaking up. Feeling something was wrong the young Avatar turned around in a snap expecting a person attempt to sneak up on her.

A sound prompted her to look down where she saw an Otter-Penguin that was smaller than the ones usually seen in the South Pole. It was roughly as tall as a four year old child leading the Avatar to wonder if it was a very young Otter-Penguin or it had some kind of stunned growth disability. The small creature looked up at Korra was a rather blank expression which was typical to their species, but yet Korra noticed the red collar around its neck with a N insignia dangling from it providing an obvious sign that it was a domesticated pet.

"Uh…Hi…are you alone on this ship?"

The Otter-Penguin kept looking at her blankly.

"Oh why am I asking you can't talk, guess I was out in the water for too long." Korra said with a sigh while at the same time she rubbed her forehead with her left hand before the Otter-Penguin waddled off.

A few moments later a loud ringing sound began to echo throughout the ship alarming the young woman as she quickly looked around the room seeing that the Otter-Penguin had went over to a small concealed button on the wall near the organ that triggered some kind of alarm. Panicking and deciding a small enclosed space like the one she was in was a bad idea of a place to fight especially since it was underwater the young woman hurried to exit the ship.

But while she passed through the navigation room she heard rushing feet below her. Without wasting time Korra hurried up to the deck where Naga was waiting. Yet before she reached the stern four men wearing brown diving suits with oxygen tanks on their backs and metal-sphere shaped helmets with hoses attached to the tanks on the back. One of them climbed onto the deck of the ship carrying a large wrench while another came with a hammer in its hands. But the other two began using waterbending to make their way onto the deck of the ship before drawing water from the sea to envelope their arms to form large tentacles for battle. Using waterbending herself Korra knocked two of the non-bender divers into the water before using Firebending to deal with the Waterbenders using the sudden use of an opposite element to catch them off guard. Her first attacked surprised the first waterbender knocking him back, but the second one was ready for Korra's attack.

The second waterbender did better against Korra, but using two waterbending strikes from the ocean and then followed up by a quick firebending strike knocked the second waterbender backwards putting him into position for Naga to attack the diver from behind knocking the diver into the ocean.

"To think the Avatar of all people would assault my crew and invade my ship," Captain Nemo spoke as Korra walked over to the top of the boarding hatch from which she had exited from.

"Are you the captain of this ship?"

"Indeed I am, but I assume you were with those pirates are you not?"

"NO I AM NOT!" Korra snapped.

"I see, so how exactly did you arrive here? A passenger on the unfortunate cargo ship that pirate ship sank?"

"Yes I was."

"So what do you intend now, attack more of my crew and take over the ship," Nemo inquired with staring at the young female Avatar with harsh eyes.

"I need to get to Republic City and I don't know if I can trust you."

"I see, but I ignore the laws of the world and the fact you assaulted members of my crew is something I am having difficulty overlooking." Nemo said while he slowly slid his left hand onto a gold device near the base of the stairwell leading onto the deck of the ship that appeared similar to a sundial in appearance with a gold and black turn handle upon it.

"So what are you going to do about it?"

"This," Nemo replied causally as he turned the switch activating one of the defensive measures upon his ship as Korra suddenly felt a jolt of electricity surge through her body paralyzing her. The young woman screamed in pain for a few moments until Nemo shut it off causing a worn down Avatar to fall stumble down the stairs before collapsing.

The last thing Korra saw was Captain Nemo standing over her while his son Jules approached from behind his father.

A/N: the song Captain Nemo was playing on his organ was, of course, Johann Sebastian Bach's Toccata and Fugue in D minor, BWV 565. Also the Nautilus in this story borrows its external appearance from the 1954 movie as well as a bit of its internal appearance too. However its size and dimensions as well as some parts of it will be alerted for the sake of story and for making it a little closer to the book as well. The same for Nemo…I decided for him go a little more based on the Disney version, but of course I will be including parts of the Captain Nemo from the book such as a modified story of his origins based from those given in the Mysterious Island.