Potterlock AU where Mycroft is a bit bigoted and Sherlock is a squib
Walking to sixth period Defense Against the Dark Arts didn't seem like a terrible thing to Mycroft while he was doing it. He hated that damned Lupin. Of course he knew Lupin was a werewolf, and he didn't understand how everyone else didn't know. Every month he would take a day off, and that day just always happened to be a full moon. Snape had made him keep it a secret after obliviating his entire class when Mycroft had revealed it. Mycroft held many secrets for teachers. He wore a time turner, for instance, and he never told anyone about that. Maybe the reason he was good at keeping secrets was because he had no one to reveal them to.
Mycroft sat down at a table, looking around for his professor. Mr. Lupin would be late, but it wasn't a full moon, so Mycroft did not understand why. Lupin came inside and all the students hushed themselves. They all had their books out and ready to learn.
"Good afternoon," he said. "Would you please put all your books back in your bags. Today's will be a practical lesson. You will need only your wands."
Mycroft rolled his eyes at Lupin's unpredictability. He placed his book reluctantly into his bag and pushed his wand to his pocket for easier access.
"Right then," said Professor Lupin. "If you'd follow me."
Mycroft was unamused by the lack of structure and how spontaneous Lupin had been. This didn't fit into the curriculum. He was sure of it. Mycroft watched as Peeves had called Lupin names. Lupin fended him off by throwing insults back at him. Mycroft saw this line of defense as weak and not very respectable. He rolled his eyes throughout the encounter and followed Lupin into the staffroom. There was a wardrobe at the center of it. The Slytherins and Gryffindors alike were gathered in front of it. It gave a jolt, which sent the class about a hop backwards.
"Nothing to worry about," said Professor Lupin calmly. "There's a boggart in there."
All of them had learned about boggarts in year three, so Lupin had almost spared them a lesson. "The charm that repels a boggart is simple, yet it requires force of mind. You see, the thing that really finishes a boggart is laughter. What you need to do is force it to assume the shape of something amusing.
"I know you all know the spell, but, while you wait for your turn, you should think about what it is your biggest fear is," Lupin instructed. "Okay, Gryffindors at the front Slytherins at the back."
Mycroft stood at the back of the line, hoping that they would be dismissed before he got a turn. The trouble with this activity was that Mycroft had no clue what he was afraid of. He watched other people's boggarts turn to mummies, spiders, and dementors, but he couldn't think of one thing he was afraid of. Maybe he was afraid of Lord Voldemort or the Womping Willow, but neither seemed like something the boggart would turn into. Mycroft kept trying to think of it, but it was too difficult for him.
"You have it Mr. Holmes?"
"No, I do not." He said. "I can't think of what I am afraid of." Mycroft pulled his wand out, nonetheless, to get ready for whatever it is that was going to be exposed to him. Lupin showed him to the boggart, who fell to the ground in the shape of his little brother. Sherlock's curly black hair splaying on the ground beneath him. Mycroft's face drained of any color that had previously there. Sherlock's skin was pale, and he was thin. Well, paler and thinner than he usually was.
Mycroft kneeled down beside him and the boggart rolled Sherlock's limp body over. The look on Sherlock's face was enough for Mycroft. Sherlock's eyes were closed, his face pulled into anything but a smug grin or sneer. He seemed utterly helpless. The boggart had intentionally left Sherlock's sleeve rolled up. Mycroft saw a number of puncture wounds in his left arm. His hooded sweatshirt barely covering a few of them that Mycroft had inspected. He ran his fingers along Sherlock's arm to find that his skin was cold. Mycroft didn't know how to handle this sight. His whole mind span around at the thought. It felt his surroundings dissolve before him. He rocked the boggart, attempting to wake him up. Nothing happened to him and he remained unresponsive. Mycroft felt tears began to slide down his face in failure. He shook his little brother quicker and more suddenly. "Sherlock," Mycroft whispered at the boggart. He started sobbing over his brother's dead body. Lupin dismissed the class and pulled Mycroft away from the boggart. He grabbed onto Mycroft's since dropped wand and handed it back to him before stepping in front of what was now a full moon.
"Riddikulus!"
"This class is ridiculous." Mycroft remarked, pulling up his bag and watching the full moon turn into a whizzing white balloon and placed back into the wardrobe.
"Have a good day, Mr. Holmes."
"Do I get a late pass? I have to go to the owlery." Mycroft said, losing his disrespectful tone.
"Of course. Writing to squib little brothers, I suppose."
Mycroft didn't know what to say to that and accepted his note, tears drying onto his face.
Author's Note: Tried to make it a bit less sad
