Winter was the time of snow and warm nights spent next to a roaring fire. Waking up in the mornings, however, was more problematic, as the biting cold tended to make disentangling one's self from the comfortable bedding an unwelcome task.
This morning, however, Princess Luna found herself soaked in sweat upon waking up, as if somepony had left the fire on all night. She opened her eyes to search for the cause of the heat, only to see her mane drooping over her face instead of flowing with the aether. She brushed it out of her way and strolled over to the nearest thermostat, only to find that it was almost a hundred degrees outside.
She stared at the little thermometer in shock. The thermostat indicated that the castle's air conditioning was blowing in full force, which meant that the temperature was even worse outside. Luna looked out the window and saw that all the snow in the castle's courtyard had melted into a small lake.
Then there was a knock at the door to her bedroom. "Thou mayst enter!"
One of her personal guards opened the door. "Princess," he panted, as if he had run a marathon through the desert. "What's going on? Most of the snow in Canterlot has melted, the sun's shinning brighter than it ever has, and your sister threatened to banish me to the moon when I tried to inform her of this!"
Luna's eyes widened, and she took a moment to compose herself. "We have seen this before. Fear not, for we shall deal with it. In the meantime, we suggest that thou inform the other guards to remove their armor and seek shelter. It may be quite some time before this problem is addressed."
The guard saluted sharply and immediately departed. Once he was safely out of hearing range, Luna let loose a loud groan, and retrieved a dark purple bottle from her private alchemical cabinet. It was half full — more than enough for the task at hand. She took off the cap and gently wafted the vapors towards her. It smelled strongly of grape, still potent after an entire millennium.
Luna tucked the bottle under her wing and made a brisk trot for Celestia's bedchambers. When she arrived she saw that the guards posted outside the door had a look of utmost terror on their faces. She motioned for them to back off as she braced herself for the difficult task ahead. After a few deep breaths, she reached out and gingerly knocked on the door.
"GO AWAY," yelled Celestia in her Royal Canterlot Voice, the likes of which had not been heard in Canterlot for hundreds of years.
"Sister, 'tis us!"
Judging by the clock down the hall, there was one full minute of silence.
"Come in," Celestia finally growled.
Luna slowly pushed open the door and walked into Celestia's room. Before the door closed, she could hear the guards outside making bets if she was going to die or not. Judging by the expression Celestia's wore — tired, with puffy eyes and a face as red as a rose — their pessimism was not entirely unfounded.
"Hello Luna." Celestia grumbled. "What brings you he–" It was then that Celestia noticed the bottle tucked under Luna's wing. "No."
"Sister, I beg of you, partake of this tincture. Everypony in Equestria is suffering from this abysmal weather!
"LEAVE! LEAVE AND NEVER RETURN WITH THAT VILE LIQUID AGAIN!"
The curtains around Celestia's bed drew closed, leaving Luna alone in the room. She sighed and walked out the door, causing one guard to sigh and pass a sizable bag of bits to the other.
"Gadzooks, Tia, thou needs to take the medicine," Luna muttered, after she was in the safety of her own room.
Luna lay down on her bed and yelled into her pillow for a good ten minutes. Once all the stress and frustration had left her system, a new idea popped into her mind. The thought was somewhat unpleasant, but there was no other choice. She had to cure her sister, for Equestria's sake. Celestia would understand.
Luna made a quick detour by the castle kitchen before she returned to Celestia's chambers. She did not even knock this time as she strolled into the room. The curtains were still pulled around the bed, just as she had left it.
"Luna, what did I say? I said to never–" s
"We are sorry sister, but this must be done!"
Luna tore open the curtains, pulled out a frying pan and hit her sister over the head with it. A resounding "clang" echoed through the castle as Celestia hit the bed like a sack of potatoes. Luna made sure the Celestia's head rested comfortably on her pillows before pour the medicine down her throat.
Luna left the room knowing that the heat wave would be over soon, and that winter in Equestria would go back to normal, or as normal as winter could be with no snow. She went back to her bedroom — which was already several degrees cooler — and immediately went back to sleep.
Half an hour later Luna was awoken by her sister yelling her name, followed by an explosion. Luna looked out the window and saw a charred hole in the wall were the window to her sister's room had been. Luna sighed and teleported over to what was left of Celestia's chambers. When Luna arrived, she saw that the entire thing had been burnt to a crisp. Her sister was lying on the burnt wood floor in front of her. Celestia tried to get up and tackle her sister, but she didn't have the energy to do so. Instead she just turned her head and looked at Luna.
"I hate you sometimes Luna," Celestia muttered from the floor.
"We are well aware." Luna kneeled down by her sister's side and cradled her head. Her horn lit up and summoned a quill and a piece of parchment. After scrawling out a quick message and sending it, she stroked Celestia's mane until a knock came at the door. Luna opened it with her telekinesis to reveal an aqua colored unicorn with a light green mane holding a notepad, who stared at the wrecked room in awe.
"Sister, we have assigned you a counselor to help you though this difficult time."
"Hello Princess." The unicorn bowed. "My name is Soothingwell, and I will be your anger management counselor for the next few weeks."
Luna gave Celestia a kiss on the cheek and went back to her room again, in an attempt at getting some more sleep, which she dearly needed after the morning's events. Ten minutes later, there came a hard knock on the door to her room. Luna sighed. "Enter."
Soothingwell bolted into the room and straight into an open closet. The door slammed shut behind her, and was followed by the sound of heavy objects being moved to block it.
"Don't let her find me," whimpered Soothingwell from deep within the closet.
"Daughter of a–" Luna checked herself just before committing the most grievous act of lèse-majesté and went to her desk for another quill and parchment.
In Ponyville
Princess Twilight Sparkle was in her Crystal Castle, pacing back and forth, trying to figure out the cause of the midwinter heat wave. She looked up from the latest book she was reading — An Inconvenient Revalation — to see Spike walking downstairs with a scroll tied in his claws.
"Twilight, we got a letter from Princess Luna."
Twilight rushed over and unrolled the letter.
Dear Twilight Sparkle,
We have sent this letter to you as an explanation and a request for help. The recent heat wave was caused by our sister going through a rare form of a fever that only she can get, a solar fever. Whenever she gets one, her temper, to put it lightly, is very short, and an "incident" occurred today due to it. We have tried anger management counseling, but it was unsuccessful. We know that our sister listens to you, and we hope that you can help her with her temper.
Sincerely,
Princess Luna
"Alright, Spike, were off to Canterlot! The student is about to become the teacher," Twilight proudly declared.
Back in Canterlot
Twilight and Spike arrived outside Celestia's bedroom, were Luna was waiting for them. "We thank thee for coming; our sister's temper is slowly improving, but she still requires your help."
Twilight puffed her chest out and held her head up high. "No problem, Princess! I've been hitting the books on the ride over, and I can assure you that Celestia's temper will be back to normal in no time!"
Luna sighed with relief. "Thanks the heavens. We will be in our quarters if our assistance is needed."
Luna returned to her bedroom, confident that Twilight would be able to calm her sister down. She lay down in her pleasantly cool bed and drifted off to sleep. Fifteen minuets later, her door flew open with a bang and Twilight and Spike rushed in and teleported into the closet that Soothingwell was currently occupying. Luna felt a scream building up in her lungs, but they gave out before she could vocalize it, and she fainted instead.