CASSANDRAS POV

"Move." He looked directly at the slightly smaller man in front of him.

"I'm sorry sir, you need to be a member of the Diogenes to enter!" the man repeated.

"My name is Sherlock Holmes, now get out of my way," he warned.

"It's quite alright. I can sign for him." Sherlock's brother's almost taunting voice sounded and my eyes immediately fall to Sherlock.

"Always lovely to see you, brother," he greeted, smiling coldly.

"You had no right breaking into her apartment, Mycroft," Sherlock hissed at him, not bothering with pleasantries.

"Perhaps we should take this in more private chambers. This way," he ordered, gesturing with his hand. I didn't move a muscle, and he went ahead.

"Sherlock," I muttered, slightly grabbing his sleeve to stop him from going after his brother; "What are we doing here?"

"I have to talk to my brother. You may wait here if you prefer," he offered coldly before leaving me behind. I glanced around me before hurrying after the two brothers, quickly finding our way into a big room with comfortable chairs placed around. A bookshelf covered one of the walls, all the way to the high ceiling, and for a second I forgot why I was even in there.

Sherlock did not.

"What the hell did you think you were doing?" he asked angrily.

"I was, and still am, protecting you, dear brother," his brother replied.

"Oh, shut up, Mycroft," Sherlock asked. 

"Sherlock, what difference does it make to you?" Mycroft challenged; "As I recall, it did not scare your last... Companion, off."

"That does not mean that you get to repeat it!" Sherlock shot back; "This is different. John was in the army, he can protect himself."

"John was a doctor, Sherlock," Mycroft reminded him.

"Besides, if you don't believe this one can protect itself, does it really seem safe to bring it along for your adventures?" he continued.

"Alright, alright, let's give it a rest," I interrupted their arguing.

"I can keep her perfectly safe, I assure you," Sherlock continued.

"Why bother, dear brother?" Mycroft asked, his voice growing more serious; "You do not need to surround yourself with regular people."

"Alright, boys, that's enough!" I sharply cut through, making them both look to me; "This is utt-"

"This is no concern of yours," Mycroft interrupted me. I looked at him with both eyebrows raised.

"No concern of mine?" I asked slowly; "Last I checked, this entire thing is my fault!"

"It's Mycroft's fault," Sherlock intervened.

"Sherlock, shut up!" I warned; "He was doing it to protect you! You need to realize that and appreciate that you have people around you who care about you and your safety! And you, Mycroft, need to realize that your little brother is no longer little. He doesn't need, nor want, you to scare off his friends!"

Mycroft glanced at Sherlock, who narrowed his eyes at him.

"You two are brothers and I can tell you love each other, so for the love of God, please act like it, because I do not like my voice like this!" I warned, pointing an angry finger between the two.

"Now, if that's sorted. Apologize," I ordered, crossing my arms above my chest.

"What?" they both asked in disbelief.

"You both heard me perfectly well!" I told; "You had a fight, and you're ready to move on from it. I know you both see your mistakes, so apologize for them!"

Sherlock and Mycroft's eyes met, them both sighing dramatically.

"Mycroft," I asked politely. He rolled his eyes and crossed his arms above his chest before looking away.

"I'm sorry," he muttered, and I looked sayingly at Sherlock.

"Cass-"

"Mycroft already apologized, Sherlock," I reminded him. He looked at Mycroft.

"I'm sorry," he stated flatly.

"Good. Thank you," I said with a small smile; "Now, is everything alright?"

"Not quite," Sherlock told, making us both look to him.

"Apologize," he stated to Mycroft.

"I already did!" Mycroft complained, looking to me for support.

"Not to me. To her," Sherlock ordered, his voice holding a certain authority I hadn't heard before.

"What? You want me to apologize to, what, your roommate-to-be?" Mycroft asked, looking absolutely stunned by the idea.

"I want you to apologize to my friend," Sherlock stated matter-of-factly. Mycroft looked at him before turning to me.

"I'm sorry for breaking into your apartment and scaring you, miss Harrington," he told me, sounding sincere - whether he was or not.

"It's okay," I told, smiling to him; "You were trying to protect your brother, I get it. Just don't do it again." I turned to Sherlock.

"Are we done here? Because last I checked, we have a murderer we need to catch," I reminded him with a small smile. He returned it slightly before turning to leave with me.

"Miss Harrington?" Mycroft interrupted us, and I turned back around.

"Will I get my money back?" he asked gently.

"Not a chance. A deal's a deal, Mycroft," I said with a smirk before turning to leave with Sherlock, who then stopped. He nodded for me to go ahead, and I glanced at Mycroft before leaving the two alone.

SHERLOCKS POV

I watched Cassandra walk out of the room before turning to my brother again.

"You asked me why bother keeping her safe and that I didn't need to surround myself with regular people," I reminded him, and he looked at me, urging me to continue.

"Because it isn't a bother, and because Cassandra Harrington is anything but regular," I told him softly. Mycroft looked in the direction she'd left.

"I'm beginning to think you might be right, brother dear," he told me, sticking his hands in his pockets; "Good luck."

I smirked before leaving the big room, finding Cassandra looking at the art in the hallway.

"Are you okay?" I asked her gently, placing myself on her right to look at the painting.

"I'm more than okay. I'm honestly kind of glad I got to meet him properly, see that he's not that scary," she told with a shrug. I smiled to myself.

"Only you would not think Mycroft to be scary. Of course, I do believe you might be the first person to get him to apologize to anyone, let alone me," I added, turning to look at her face, even though she was still enchanted by the painting. She let out a small hum as she smiled.

"You're cute. The two of you," she mentioned; "I'm glad you had each other growing up. Must've been hard."

"What do you mean?" I asked, my eyebrows gently furrowing on my forehead. Her eyes finally met mine and she searched them.

"Growing up. You weren't... Born like that," she said softly.

"What, a freak?" I teased, but there was no joking to see on her face.

"No. Able to deduce," she explained, putting her hands in her pockets.

"I'm a high-functioning sociopath," I stated, looking back at the painting.

"I know. But sociopaths aren't able to deduce, Sherlock. You are. And your brother. Either, your brother would have been a complete psychopath he would've forced you to become a sociopath, but he's not, so I'm guessing your parents must have taught you deducing, but... Well, I guess their methods weren't always as one could have hoped. That's why you're a sociopath, isn't it?" she questioned, still looking at me.

My eyes frantically ran over the painting, avoiding listening to the facts she stated.

"He always looked over you as a kid. Your parents were tougher on you, they wanted you to be able to function and... Pretend, as well as he could, that nothing was going on in your home, but because he stood up for you, you weren't forced to learn that."

"And that's why I can't act normal?" I asked her, desperately trying to ignore the emotions gathering in a pit in my stomach.

"No. Well, yeah, but... It's also why you get to become happy someday," she mentioned. I looked at her, our eyes once again meeting.

"Well, Mycroft is miserable. Everything about him screams it," she explained, noticing my confusion; "He's lonely, not in touch with his emotions, has to hide everything he is and everything he carries. You're unhappy because you're not in touch with your emotions and because even though you don't have to hide who you are... People don't accept it."

"How do you know all this?" I asked her, my voice suddenly hoarser than a minute ago.

"I'm sorry, I went too close, didn't I?" she realized; "I'm sorry, I didn't mean to."

"It's fine," I stated, looking back to the painting.

"You can't deduce. How do you know these things?" I asked again.

"I'm just good at reading emotions. Psychology fascinates me, and you fascinate me," she explained with a shrug.

"I fascinate you?" I questioned.

"You don't want to feel," she told slowly; "and I get that, I wouldn't either if I were unhappy. But it's just... The things that make you unhappy, they can be removed, you know?"

I looked at her, not understanding.

"You're lonely," she told, looking at me again; "But you don't have to be. I bet you feel lonely because John left to live with Mary, and you feel like he's left you to be alone again, but it could just as easily have been you who'd found someone to be with."

I snickered, looking away.

"You don't believe me," she stated, looking directly at me. It wasn't a question, she wasn't looking for me to agree or disagree. It was a simple statement. I didn't believe her.

"You think so lowly of yourself, Sherlock," she then told, looking back to the painting; "You don't think anyone can love you."

"Even if they could it wouldn't make a difference," I admitted; "Because I could never love them."

"You love John," she commented lightly.

"As a friend."

"Because you let him in your life as a friend," Cassandra argued; "If you met someone and decided to let them have a place in your life as more, I believe you could love someone. Just like someone could love you."

"Even if someone did love me, they wouldn't be able to be with me," I told quietly; "I'm not someone... You're with."

"Why not?" she challenged quickly.

"Would you want to be with me?" I shot back, looking at her.

"I don't see why not?"

I furrowed my eyebrows.

"I mean, not that I want to be with you," she corrected, and I looked back to the painting; "Just, I mean, if I were into you and you were into me, I don't see why we couldn't make it as a couple."

"Let's get back to the case," I muttered, turning around on my heel, leaving her to hurry after me.

EXPLANATION:

Sherlock is a sociopath. He learned to control his emotions after living with Eurus, but having no memories of her and Cassandra not knowing about her, she assumed their parents were to blame.

That's why I added the bit where it said that if Mycroft had been a psychopath, it would have added up in her mind, but after meeting Mycroft she went to assume it was their parents. Eurus is the missing piece here, but obviously Cassandra doesn't know that and doesn't question it, not having met the Holmes parents.