Do you wanna build a snowmare? Or is it a Snowman?
Prolouge: The Frozen Crystal Heart
In the Frozen past...
...................................
It was wintertime, and a lot of hard-working ice harvesters were worked in the field to harvest ice to trade and store. Some Unicorns were harvesting frozen blocks of ice from a river and some Pegasi were lifting the blocks over to some Earth ones were stacking up ice blocks to store as ice for the next Summer; while in the palace, the King and Queen, (or Prince and Princess - as they liked to be called) were sorting out the prices for the ice. The ice workers were singing about how at this time, the Crystal Heart is frozen and only the love of the crystal ponies, kept the heart's power alive. (However, it was dwindling due to the cold, which caused there to be even colder.)
A 4-year-old harvester rookie, and his baby reindeer Pokemon, Stantler (named Ben), was bouncing after his young owner. Because the boy's dad was working so hard and singing, he did not notice that his boy (who was prohibited entering the field yet) was playing and watching his daddy work from behind him. While the boy's curiosity was getting the better of him, he searched through his dad's satchel to see what he had in there. After rummaging through clothes and food, the colt found a picture of the King and Queen. The colt then recalled that his dad loves his wife but when he was a colt, he liked the Queen. He could not do well in his job until he became an adult, (and was also too afraid to talk to the mare), so he missed his chance when Shining Armor came to love Princess Mi Amore Cadenza.
Because the boy had been told about that occurrence, and how the royal couple had already lost a natural-born-alicorn baby girl many years before becoming recently pregnant - (for Flurry had flown up to the sun near space despite her parent's warning,- and then cried for the trio. He then vowed that the next time a baby princess was born, he was going to marry her and treat her right with lots of love!
Present day...
A baby white unicorn filly with baby green dot-like eyes peeked through the covers of her cot. She had just awoken from the cold and the sight of the beautiful snow outside. The filly was a princess, but only three-and-a-half, but could already levitate things to some extent. She had only just learned to say her sister's name yesterday so she said it in a cute way, or a shortened way. There was a lot of love in the Crystal Empire for King Sombra had not taken over it yet. It was winter, so the Crystal Heart had kept the frozen north but not the usual cold felt during this white season.
It was night-time and it was freezing, so the girl was getting antsy. The filly cried a little as she levitated the bars of her pink cot down; it is extremely difficult to carry things with your mind! The cry, however, was not enough to wake up her parents or her big 5-year-old sister in the next room. It was really cold, so the foal wanted to see how her sister was doing and maybe snuggle up with her warm body! The baby then crawled across the floor and opened the door with magic. It took her a few minutes, but she finally remembered where her sister's room was and crawled up to her bed. She then saw that both sisters' clothes for the morning - thick coat-like dresses, wooly mittens, and cute ear warmers were on her sister's table. Afterward, she remembered that her sister had told her that there was something that foals build in the gorgeous but ridiculously cold snow.
She tried to remember what name it had. Was is a snow...man? A snow-woman? A snow-colt? A snow-filly...foal...or...mawe? Actwally, they go by all of those hilawious names! Suddenly, the baby wanted to build one and forgot her coldness. While turning a little bit of her attention to her magic in order to keep the clothes floating, the filly bounced up and down on her sister's belly to wake her up. BOING! Boing, boing, boing, BOING!
"AH! OOF! Ow! Sweetie BELLLLE!" The unicorn Princess Rarity screamed as she woke up with a start. She had just been dreaming about finding her true love and marrying a noble or a prince. She was upset that her tiny baby sister would do this to her - how cruel! She then rubbed her aching belly and wondered and was annoyed by the fact that Sweetie even knew how to get to her sister's room! "Don't do that! What do you want? You better make it snappy - and quiet - you DON'T want to wake up our parents!!"
"Sowwy Wawity!" Sweetie apologized, then asked, "Do u wanna bwiuld a snowmare? I know u can mak one wid youw horn and youw adorable hoofsies!"
"At THIS time of night?! And, how do you know about my powers so well?!"
Sweetie Belle shrugged, starting to put the clothes she was carrying onto herself and her sister in a rough way.
"Sigh...oh well...I wanted a sister and I GOT one. I have to live with you! I love you, and I'm actually very impressive how you made your way here! He, he! HUH?!" Rarity was dumbfounded - Sweetie had just woken up from a nap and was only just fitting her own dress on. "Here, let me put the clothes on PROPERLY!" Rarity glared at her sister who had her dress on upside-down. She was appalled - how did Sweetie put her sister's dress on right, but not her own? As she was fixing the dress, she said, "We can do it in the great hall, where mother and father won't here. Remember, be CAREFUL! You are my sister Sweetie Belle - you are very apt to getting into mischief and trouble! You also have to stay close while I am doing my magic! OK, Sweetie?"
"Ok, Rare!" Sweetie responded, "This'll be fun! Oh yeah, and I wub you two sistw!" 
The sisters then ran and bounced into the great hall, ready to warm themselves up with fun and the clothes they were wearing! Rarity then sat down in the middle of the circle and concentrated. Her magic was very powerful - it can create beautiful snow as well as do what other unicorns do. Rarity will have natural-born alicorn princess-worthy power once her wings form and grow. She will be the strongest alicorn that will grow wings, and who was not born an alicorn - making her a worthy protector of the Empire, and soon - Equestria!
However, Sweetie only has normal unicorn magic, and will only have normal alicorn magic when she grows up. She had decided to become a princess of nature since she loves grassy fields, will love planting, and is a natural phenomenon and has an abnormal sister who controls the cold. Until this night, their parents had wanted them to become future rulers of the Crystal Empire, sharing love, light, diamonds, nature, and snow with their subjects. Unfortunately, this didn't happen, as an accident is about to postpone the coronation for about 21 years.
Woosh!
Rarity made an upwards circling motion upward with her front hooves, and as her horn glowed, the magic of the snow appeared in her hooves and spiraled out into snow-fireworks. Boom!
The snow exploded quietly until it came down not as hail, but as wet rain on the duo. "Woo! Rare, wet's do it again!" Sweetie screamed.
Rarity did as her sister said, while also creating a snowy wonderland with a snowslide. Once the rain fell on the sisters again, they created snow forts and snow angels, playing against each other and having the time of their lives!
Finally, Rarity created the snow-pony version of the Pokemon Snover. "Hee hee! I'm Snowlof the Snover!" Sweetie made him say while moving his stick arms to wave. Rarity then created a snowmare named Clarity the crystal. The duo snowponies were made to hug and kiss one another. The sisters giggled, as Sweetie climbed up onto the snow-slide and rushed down it. Rarity had put a pile of snow down at the bottom of it, but after a few times, Sweetie accelerated herself with her magic. WEE! Rarity gasped as her sister was about to fall down past the soft lump of snow.
"What?! Sweetie Belle! NOOOOO!" BAM!
In her haste to save her sister, Rarity then shot a stray beam of magic to create a magic carpet to float her sister down to safety. However, her strong fear at that moment made it impossible to aim correctly, and she ended up hitting her own sister. Rarity gasped once again as she rushed over to her as Sweetie Belle mumbled, "I'm sorry Wawity, I went to fast...", then fainted. Her sister was starting to cry now, and increasing fear was now her winter wonderland to a wasteland as a thundery snowstorm appeared. Rarity didn't care however, she just wanted to make sure Sweetie was alright, put her on her back, and ran away quickly to get her parents!
After getting help, Rarity and her parents went to see the Hoopas or the Pokemon trolls, to seek help.
The ponies explained the situation and said that Rarity must lock her powers away since fear brings out the worst in them. The Hoopa's magic helped restore Sweetie, but she forgot everything about Rare's powers - and the crystal ponies didn't know about anything of Rarity's powers. The Hoopas were sorry- there was nothing that they could do other than explain this sad news. It was a bittersweet ending, then a horrible one - but in to protect the whole empire, the Hoopas had to 'lock' princess Rarity's powers away, while saying that she could become a monster and that they needed to save Rarity's sister and the Empire for the good of ponykind.
After hearing this, it caused Rarity to become even more distraught than ever. Why was I ever stupid enough to cause this?! 
Ever since then, the royal family's depression caused the Empire to lose some of its love, starting the point in time when in less than 30 years, King Sombra was going to take over the Empire. Ever since the accident, the sister's parents and their advisers had to rule since then since Rarity did not want to come out of her room. Her parents had to move all the necessary things for Rarity's life to her room, and she would always put used items and food outside her door and talk to you from there, no matter what the occasion. During the first year after what happened, whenever Rarity stepped one hoof out into the hallway from her bedroom, (after Sweetie asked to build a snowmare or come out and play), Rarity would always falter and fall to the floor, suddenly feeling very cold. She felt the fear and sadness from last year and kept it in her heart. Sweetie Belle didn't know what was doing on, and help a huge amount of confusing in her heart. She wondered if Rarity was sick, confined and trapped in her own room, or annoyed at her. Next year, Rarity refused to come out of her beautiful diamond-encrusted room altogether, thinking it was her fault that her sister almost died because of her, all those years ago.
8 years later...
"Do you wanna build a snowmare?" Song
"Rarity?"
Rarity silently sighed as her 10-year-old sister said her name and was about to knock on the door for the 5,783rd time since the Accident. She had just gotten her cutie mark in singing and by being a cutie mark crusader with her three friends. It is a shield with three colors - representing Sweetie's friendship with her friends. It also had a star with a song note in it - recognizing Sweetie's strong love for singing!
Rarity had gotten her mark a year after the Accident. It was three blue diamonds, with one bigger that the rest. This one has a ball of snow and a snowflake inside of it. Rarity had received it when she found beautiful diamonds that had been in her favorite rock outside her window. She then became a lone dress-maker.
Rarity thought about how Sweetie Belle is such as good, (and loud) singer, that not only did it cause her plants to grow like wildfire, but also caused her sister to not be able to fall asleep while Sweetie sang. Sweetie did not like going fun places without her sister, but this was her life now. She was going to bug her sister until she told her what Sweetie had caused to make Rarity cry. Little did Rarity know, some nightmare energy from the moon (which was now in her room) was growing while feeding off of her fear.
Rarity braced herself for the impending song. Because of the huge amount of colds, disharmony ,and sadness in the Crystal Empire, the ponies couldn't create as much love as usual, making it always snow. This caused Sweetie Belle to have to plant in a secret greenhouse garden in the palace to be able to keep at least one place in her corner of the world green and colorful. Ergo, she ALWAYS sings the "do you wanna build a snowmare" song to Rarity! Rarity loved her sister, but she was fed up - though she had to endure this torcher!
"Rarityyyyyy!"
Knock-knock-knock-knock!
"Do you wanna build a snowmareeee?!
I haven't seen you in a while....! 
Don't know what I did to hurt you..., please TELL ME sister, WHYYYYYYY?!
We used to be best buddies, and now we're not!
What are we going to doooooo?!
Do you wanna build a snow-mare, it doesn't have to be a snowmare?!"
"Please leave me alone Sweetie Belle!" Rarity cried before Sweetie could explain her day as to elongate the song.
"Ok...fine............!"
..................................................
5 years later...
Rarity was accidentally shooting lots of crazy magical power beams to cause ice crystals from her horn, causing her room to freeze.
"Help me Mummy and Daddy! The magic's getting stronger!!"
"Calm down", Cadance answered, "Fear makes it stronger - use love!"
"Let me help", Shining Armor calmly approached his daughter.
"No! Stay Back!" Rarity stepped backward. "I don't want to hurt you like I did with Sweetie Belle!!!"
After her parents left Rarity's room crying at their daughter's state, they decided to increase and magnify the power of their love spell to help out their daughter, but it would be to no avail. Their love for each other was growing weak amongst this chaos! However, at least they were able to find some gloves and that would some of their daughter's power down. Her hooves and horn were connected to Rarity's magic so there was no need for her to wear a hat as well.
"Conceal it, don't feel it, and don't let it show!" Shining armour had to Rarity said a few years ago. He regretted those words, as Rarity followed them to a "t" the best she could. Shining wished he could take back his influence on his daughter - she IS an ice princess, hiding the power isn't good for her health!
Knock, knock, knock, knock, knock! "Hello? Rarity?!"
GRRRRRR! Rarity was ready to scream! She had just finished her latest frock and she knew that her sister was going to sing the Song again! Dress-making occupied her time as to not give into the darkness that was in her room - but not annoying little sister was back again!
15-year-old Sweetie Belle filled up her lounges to sing.
Knock, knock, knock, knock, knock!
"Do you wanna build a snowmare...or ride our bikes across the haaaallllll?!
Save me from this boring place - I've started taking to the pictures on the waaaaallll! - Hang in there John!"
Sweetie stood on her bike and rode it downstairs to a sofa, jumped off the bike to lie on it and talked to the pony in the painting. He then thought, Was that filly just talking to ME?!
The rest of the Duchess Teen Cutie Mark Crusaders came in the room, to check if Sweetie was free to discuss political matters. They then say that Sweetie was singing to her sister, waved to their friend, (who waved back), and left the room until Sweetie was ready to talk with them.
Sweetie Belle gave Rarity the stink eye and a grimace. She then started to cry as she continued,
"I only have my frieeends,
They were there for me,
Wheeeeen I made my marrrrk!
Rarity, I kind of hate you....
But would you like to build a snowmare?!"
Sweetie came back upstairs and screamed right in Rarity's door while crying.
"Go away Sweetie!" Rarity yelled louder than she had every done before. Sweetie thought that her sister was just lashing out on her, however, the nightmare was energy increasing her anger.
Sweetie cried, "Ok...sniff...bye..."
.............................
5 years later...
The parents then went to see a wedding of Rarity's cousin Princess Appunzel and former thief Caramel. They said it was extremely important - that they had been 'forced' to go by the ruler of Equestria. These words, however, where their last - and the ones their daughters help them accountable for. The parents would have to pass away so that the sisters would have a pure love for each other. However, that means that the completed spell would never be complete without that extra bonding time.
The parents went away in the royal carriage to take a ship through the sea. Even though she ship had been made to avoid any capsizing, one of the unicorn fillies on board n the deck was playing blasting tag with her friends, accidentally shot magic into one of the sides of the ship. Unfortunately, the adults were all in the middle of the ship or at the top; so they didn't know that a huge hole had been made in the deck. When a terrible thunderstorm approached, the conducting water at the bottom of the ship made easier for lightning to strike the huge royal ship and tear it apart. Sadly, the ship then capsized, and Cadance and Shining Armour never got to see the wedding, or their daughters again.
There was no news of the parents for six months. After a long time of searching and hoping, royal messenger explained the tragic news - even though they weren't ready, the girls were no longer princesses in training - they are now TRUE Princesses....rulers of Equestria! Sweetie Belle then came to her sister's room to tell her the bad news...their parents had died. They both cried, almost cursing the barrier of the door between them, They SO wanted to hold each other in their forelegs right now. They kept mumbling "I'm sorry" to one another and looking at each other through the keyhole in the door. The nightmare energy had increased so much that Rarity was starting to actually transform into a nightmare. It would only be the love for each other that would temporarily stop Rarity from transforming for the next three years.
"Sniff...sniff...Rarity, I love you," Sweetie Belle said, then sang in a shaky voice:
"Sister, I KNOW you're in there.
Just wanted to say sorry!
I know this must be hard on you too;
I apologize, for being so meaaaaaan!
We only have each other,
It's just you and me...
WHAT ARE WE GONNA DOOOOO?!
Do you want to build a snowmare...it doesn't have to be a snowmare....!
Rarity...I'm SO sorryyyyyyy...WAAAAAAAAA!"
Sweetie broke down crying as her sister sang again for the first time in Sweetie's life that she could remember. Sweetie was heartwarming.
"Do you want to build a snooomareeee? I really want to build a snowmare, but I'm afraid I cannot yet...Though I loooove yooooouuuu!"
Sweetie Belle answered, glad for the sisters' first duet in her long life. "I love you tooooo..." 
