Antipodes

Antipodes is a fanfiction written by PK. It takes place 10,000 years after an event known as the "Great Cataclysm", when Celestia and Luna disappeared, without a trace, and the sun and moon froze where they were in the sky at that point.

Plot
10,000 years after an event in which Celestia and Luna disappeared, and the sun and moon froze where they were in the sky, a unicorn named Jigsaw and a pegasus named Tiptoe are walking to the central lake of the cave in which they live, in order to perform maintenance on the water system; for after the Great Cataclysm, eventually, the sun side of the world got too hot to be inhabitable, and so the ponies shut themselves off in caves. They get to the control room, and are about to perform the routine checks, when a monster attacks. They barely escape the monster, but unfortunately, the control room sinks to the bottom of the lake, so they have no way of getting back to where they came from.

Realizing this, they continue on until they reach a door. Fearing that it might lead to the outside, Tiptoe hesitates, but eventually is convinced by Jigsaw. He uses his magic to activate the mechanism to open the door. Inside, they discover a subway apparently formerly of the "Fillydelphia Public Transportation Network." Jigsaw uses his special talent, skills with gadgetry, to get the car up and running again, and they begin their ride on the subway car.

Three days pass, and they haven't seen anything besides empty stations, according to Jigsaw. The stress of the journey, along with the lack of food, eventually get to Tiptoe, and she snaps at Jigsaw, who was telling about how he rewired the subway car to run on magic instead of electricity, and how the two don't mix very well. Eventually, she apologizes, and Jigsaw admits that Tiptoe was not his first apprentice. He originally had an earth pony named Antimony as his apprentice, but one day, they encountered a cave ogre. While Jigsaw ran and hid, Antimony tried to stand her ground, but was killed. After that, he says that he worked alone until the Tribunal forced him to take on Tiptoe as his new apprentice, and he vows to never leave Tiptoe to fend for herself.

Soon after that, the subway runs out of track, and skids to a halt, breaking beyond even Jigsaw's ability to repair it. So they walk, eventually reaching the end of the cave, when they encounter sunlight, and think they are about to be immolated by it. When they are not, however, Jigsaw realizes they found the temperate zone, which was believed to be an old pony's tale. Feeling the warmth of the sun, and seeing the blue sky for the very first time, Tiptoe is inspired to soar. Eventually, she returns to the hole, and lifts Jigsaw out too. It is then that they make the observation that the sun and moon don't look like they did in the illustrations of the books they'd read, but rather, like they are dying.

Jigsaw
He is the main character, and a unicorn. His special talent having a large amount of skill with gadgetry; for instance, he sees an old world subway only once, and is able to use his magic to not only completely put it back together, but change its power source from electricity to magic. Additionally, he has the ability to gather shards of Celestia and Luna (what they were reduced to after the Great Cataclysm) inside his body. It is currently unknown what will happen when he has gathered all the shards.

Tiptoe
A pegasus, her special talent is stealth. That was the reason she was assigned to Jigsaw in the first place: to help him avoid the potential monster encounters inside the caves. She's a bit sensitive about her race, as pegasi are usually looked down upon in the caves; being that there's no wide open spaces for them to fly, and they're a dying race (being increasingly replaced by earth ponies). In the later chapters, she and Jigsaw enter into a relationship.

Incendia
A unicorn introduced when Jigsaw and Tiptoe reach Stalliongrad. She is the leader of the rebellion against the ruler there, and her special talent is being able to create flames, as well as burst into flames herself whenever she's upset, or concentrates very hard. Later on, she begins to travel with Jigsaw and Tiptoe, helping them with gathering up the shards of the princesses. It is revealed in the later chapters that she is also in love with Tiptoe.

Tantalus
A being that has survived the entire 10,000 years since the Great Cataclysm. Other than the fact that he is the combination of Spike and a being of darkness (the antithesis to Celestia and Luna, in fact), not much is known about him. He claims to be almost entirely the being now, but Jigsaw suspects he still has more of Spike left within him than he likes to let on. He also seems to want the shards of the princesses.

Stalliongrad
The first major city Jigsaw and Tiptoe travel to. Here, they meet Incendia. Originally, Stalliongrad is one of the few remnants of the old Equestria, but is run by a tyrannical dictator known as Rubidium. He uses the citizens to keep himself young: he uses some sort of magical method to drain the youth from them, and implant it in himself. It is surrounded by a barrier keeping Tantalus at bay. It is eventually crushed when Jigsaw acquires the shard of Celestia being used to power it, and Tantalus comes and kills Rubidium, with whom he'd had a grudge since around the time of the Great Cataclysm. It is implied that the grudge had something to do with Rarity.

Totemhoof
The second major locale that the group travels to. It has a large population of refugees from Stalliongrad. They are Luna worshippers; as an old priest named Moonbow explains, while they respect Celestia, they identify with Luna more. When Jigsaw acquires the shard of Luna there, it destroys their defenses against Tantalus's followers, but thanks to a Lunar Battleship, which Jigsaw finds when Moonbow takes him to a normally off-limits area, the group is able to destroy enough of Tantalus's followers to make fending off the remnants feasible for the residents. Plus, as Tiptoe tells Jigsaw when he is recovering in the hospital later, Moonbow knew of a prophecy telling that that was what was going to happen some day, and that now that the Luna shard is gone, it shouldn't be a target of Tantalus anymore.