The house was quiet, only the sound of honey nut oats being chewed filled the air. The mid-morning sun was already present, covering parts of the kitchen in broken sections of light, courtesy of the large glass windows. Sitting at the kitchen table was a lone stallion, casually munching away at his breakfast, while he fought to keep his eyes open.

Shining Armor grumbled, his head constantly throbbing thanks to a study session from the previous night that went on longer than it should have. Thoughts of guard protocols and regulations flooded his mind, while at the same time images of flasks and beakers tried to fight for his center of attention. He hated studying for exams and usually just coasted by in school thanks to him having a better understanding than most, but sadly certain subjects and failing grades made him put in more effort. He wouldn't have cared otherwise, but the idea of attending school for an extra year because he was short one credit wasn't something he didn't want to deal with.

Guard duty and security took over his mind as mundane thoughts of positions, salutes, and general duties played out. He hated the constant stream of thoughts, but thankfully not as much as his school ones. It was a future he was setting himself up for. He was already guaranteed a guard position, thanks to his father being Captain of the Royal Guard himself, but Shining knew he had to show the effort and drive to become that as well. He just wished both school and his guard pony exams didn't fall under the morning and evening of the same day.

Thankfully it was a few days away, and he instead focused on the fact it was a weekend. He usually slept in, enjoying the blissful respite from a long week of schooling, but this week he wouldn't get that. He continued to eat and struggled to keep his eyes open, but he stayed focused enough to read over a letter left for him by his parents. It was short and simple; both his parents had to tend a royal summit up in the castle and they apologized for having to drop foalsitting duties on him. They also took Spike for special reasons, so it would be one less sibling to worry about. He didn't mind it, since they always paid him for it, but he wished they would hire a proper sitter so he could enjoy the small amount of time he had off.

He didn't foalsit often, thanks to his mother being a stay-at-home parent, or even the fact that his younger sibling was usually up in the castle with the princess, eagerly studying magic under her wing. Sadly thanks to the royal summit, the princess was preoccupied and unable to teach, and though his mother was usually home, she generously offered to help prep for it, thanks to her old occupation of working within the castle itself.

His thoughts went to his sister. She was young and very book smart, and though they had a very active childhood together, she was slowly starting to grow out of the usual activities they did. She was growing up, showing more interest in a magical academic pursuit in life, and most of the time she was at home, she usually stayed in her room or in the house library, studying spells or reading up on Equestrian history. She was a shut in and didn't go out much, but from what he knew, she had a few friends she mingled with on occasion. Nothing concrete though, which was worrying in a way, but Shining himself wasn't a social butterfly either. Both ponies kept to themselves and opted to pursue their life goals from their own comfort zones, and both just happened to enjoy that from the comfort of their own homes.

The sound of hooves dragging across the floor filled his ears and a loud yawn quickly followed. He grew more alert but he didn't look behind him, knowing very well it was his sister.

"Morning, Twiley," Shining mumbled, trying his best to not sound miserable from his lack of sleep.

"Morning, Shiny," Twilight replied, her voice sounding like she didn't get a good night's sleep either. "Where's Mom and Dad?"

"They took Spike and left early to attend the summit, since a dragon emissary is visiting," Shining replied as he took another mouthful of oats. "It's just you and me until the evening."

"Oh," she spoke, her voice filled with worry, as she trotted past his seat. "I guess I can't go to the doctors anymore."

Shining went quiet as she walked by, and he couldn't help but notice she was frantic yet awkward in the way she walked. Her mane she always combed was bedridden and stuck off to the side, and her tail constantly swished almost in an impatient manner. Her breathing was slow and heavy and a hint of perspiration covered her whole body, making it shine with a wet glow. It almost looked like she showered, yet thanks to her mane being completely dry, he knew something was off.

"Are you feeling okay?" He asked as she opened the fridge and magically grabbed a jug of milk and an apple.

"Think I'm coming down with something," she replied with uneasiness in her words. "Woke up feeling all hot and sweaty, so I'm wondering if I got a fever of some kind."

"Did you sleep well last night?" He probed further, hoping to get answers or hints to what was wrong with her.

"I slept fine," she told him as she poured a glass of milk and put the jug back in the fridge, before trotting to the table to sit. "I just woke up feeling… off."

"Off?" He quoted.

"Yeah, I just don't feel myself today," she replied as she neared. "It's not depression or anything, it's just my whole body feels weird in a way I can't describe it."

Shining stayed quiet, trying to make sense of the situation. He stared a few seconds longer, taking in her appearance as his thoughts drifted. She recently went through a growth spurt and no longer looked like a filly. She was still young, being the ripe age of fourteen, and she was starting to blossom into a proper mare. She was still small though, and being a stallion that was almost fully grown himself, he still towered over her.

His mind took notice of the more particular parts growing, specifically her flank, legs, and her butt, but he shrugged it off as if it was nothing, doing his best to silence the more lewd machinations of his teenage mind. He wasn't immune to his heterosexual thoughts, considering he dealt with females in school often, but he knew better than to look at his sister in that same light.

Shining continued to watch and hoped he could figure out what was wrong with her. It wasn't until she started to hoist herself up on the chair that made the gears in his mind start to turn. He watched her expression cringe and tense up as her rear came into contact with the smooth surface of the wooden stool. She stifled something under her breath and her lips trembled for a moment. Something clicked in his mind and his groggy mind jolted fully awake. He knew that look on her face, something he saw a lot of in school just before spring break hit. Mares would come to school with that same frantic and awkward step, and when they sat in their seats, their expressions were the same as Twilight's currently was. Sometimes they would moan and sometimes they would remain quiet, but Shining knew exactly what was wrong.

His sister was in heat.

He continued to stay quiet and he could tell his sister was starting to get confused by his awkward silence. He didn't know what to say, but his mind screamed at him, telling him to leave and lock himself in his room. Being around a female in heat was never a situation he liked to be in. It was awkward and uncomfortable, especially at school. Most of the time the mare would distance themselves from others, hoping they wouldn't give into the temptation of the situation, and thankfully most of the times they were successful.

Sometimes though, it got so bad that mares would have to go to the nurses office to be dealt with. He didn't know what they did, but when they returned to class, their heat cycle was gone. The answers were always mixed; some mares said they got rutted into oblivion, while others said a spell of some kind was used. He knew the latter was more likely, but in the back of his mind, the former interested him more. He wasn't oblivious to the topic of sex. Though he never engaged in sexual activity with others, he had a basic understanding of it.

He let out a deep sigh and started to breathe in through his nose. He instantly regretted it as a familiar scent started to fill the room. He knew that scent well, an unpleasant sensation that triggered something in his mind. He looked at Twilight who was focused on drinking the last bit of her milk, while his eyes caught sight of her tail. Even from her seated position, it stood upright, constantly fanning and flickering about, accidentally spreading her scent. The more it spread, the more anxious he grew, and eventually he swallowed back a building tension in his throat as he felt his loins start to stiffen.

"You should try laying down a bit longer. Maybe you didn't get enough sleep," he answered finally, hoping to distract himself before lewd thoughts started to surface in his mind. "Or try having a cold shower."

"I don't know, but I think you're right," she replied, as she put the empty glass down and grabbed her apple. "What do you think is wrong with me though?"

Shining didn't want to answer that question, knowing very well the answer to it. It wasn't out of spite, but rather the fact she was oblivious to the situation. He feared telling her she was in heat would cause her to panic, and she had a tendency of overreacting to things when something didn't go her way. He didn't want to deal with it, at least not alone, and the idea of making sure they didn't linger around each other for most of the day became present, as well as another thought. She was young but considering her age, it shouldn't have been her first heat cycle. She would have experienced her first cycle last year, and thankfully he didn't have to deal with it then. He just wondered why she was acting like she didn't know. Maybe she was trying to not let him see it; maybe it was all an act, or maybe it was something else. He wanted to probe her for answers, but as the scent started to become much more prominent, he knew it was better to not stick around her.

"I'm not sure, but I can head to the library and look something up," he replied, trying to figure out an excuse, while at the same time he did his best to appear confident. "There may be a spell I can find or some sort of explanation to what's wrong with you. While I do that, you should go shower and get some rest. Just let your big brother figure something out for you."

Twilight said nothing and stared quietly at him. For a brief second, he wondered if he pushed too hard to be away from her, but as a warm smile appeared on her face, he knew otherwise.

"Alright, I'll go get some rest," she replied, her voice no longer carried the uneasiness it did prior. "Thanks, Shiny. You're the best."

Shining smiled in return and watched his sister raise from her seat. Her expression tensed as she moved but she quickly composed herself as she began to trot away. Still holding her apple with her magic, she took a bite, and Shining couldn't help but notice a small sashay in her hips as she walked. It felt off to him and he closed his eyes, fearing his mind was working against him. When he opened them back up, she was walking the same way as she came into the kitchen earlier. He started to sigh, loathing the state of his sexually active mind, but lost his breath as her rear came into focus. As she moved under one of the broken beams of light, her back end glistened and he quickly looked away. What he saw wasn't a machination of his mind but instead was something very real.

He squeezed his legs together, trying his best to forget what he saw, but it only got worse as he clinched his eyes shut. He saw that crystal clear image floating in his mind, taunting him as the sight of a very aroused mare's nethers dominated him. A very wet and puffy vulva stared back, voicelessly clamored to be filled and sated, while an equally wet and winking clitoris yearned to be touched and caressed.

Twilight left the kitchen, the sound of her hooves beating against the floor faded as she went deeper into the house. He opened his eyes and took a deep breath, letting out a sigh shortly after. He gave his head a shake, and the image began to fade and distort until he let the thoughts from his study session early on start to play out. Eventually the image faded from existence and he breathed a sigh of relief. He stared forward, his eyes unfocused as he stared off into nothingness. All the times he had to deal with a mare in heat, he was told to ignore her. He wanted to, but with him and her in the house by themselves, it was going to be tricky. Coupled with the fact that he had to watch over her and that they were going to be alone until the evening, made Shining dread the day. He hoped and prayed the library had something to fix the situation he was in.

He looked down to his bowl and noticed a few oats and milk were left on the bottom. Two oats remained, one half broken while one end of it overlapped into the round hole of the other. He stared and grumbled at the image, before he lifted the bowl with his magic and drank down the rest.

"It just had to be one of those days, didn't it?" Shining asked himself, grumbling as he looked down at his lap, noticing he was no longer stiff. "Well… better not waste any time and start searching."

Author's Note

Patience is a virtue. The next 5 chapters will be published throughout the week.