"You should have told me," said John from across the cab. These were the first words he had uttered to Sherlock since he had gone to fetch him from the hospital.

"Like I said, I had everything under control."

"Stitches and a concussion don't classify as 'under control', Sherlock. I've told you that already."

"John, it was only a minor concussion, there's no need to fuss."

John huffed, and opted to look out the window instead of replying. Sherlock could tell by his tense shoulders and pursed lips that he was truly angry, and didn't want to cause a scene in front of the driver.

Ten minutes later, they were finally home. John paid the cabbie and made his way upstairs, Sherlock following closely behind.

"You can't keep doing this, Sherlock."

"John, you're overreacting." He closed the door behind him and took a step closer to John. Even if he didn't understand what he had done wrong, John always appreciated intimacy. He tried to grab his shoulder, but John shuffled away from him.

"No, Sherlock. You lied to me. You sent me away looking for some fake clues, while you went to have a little chat with the killer." John's hand tremor came back in the middle of his speech, and he dragged a hand over his face, trying to calm down. His next words were merely a whisper, his eyes looking over Sherlock's shoulder, avoiding eye contact. "You could have died."

"John." He carefully took a step closer and took hold of John's arm, giving it a light squeeze. "I knew what I was doing. I was never in any danger. I know you're mad I sent you away, but I didn't need you there."

"You didn't need- But why did you lie to me? Couldn't you just tell me to stay home?" John had tensed up again, and Sherlock could see he was trying very hard not to pull away.

"John, we both know you wouldn't have listened if I had told you the truth. Lying is always the best option when you get stubborn." He tried to make it sound like he was teasing him, since recurring to humor was a good tactic when John was in a bad mood. But when John's face closed off, he knew it had been the wrong thing to say.

John shook Sherlock's hand off his arm and went upstairs, to his old room. He didn't say anything else, nor glanced at him again.

"Sherlock, hello. Did you come to get those thumbs you asked me for?

"Not exactly. Though, I will come back for them later." Sherlock took a deep breath, his fight with John still running through his head. He tried to partially clear his mind and stared at Molly, as if expecting her to understand his problem without having to say it out loud.

"Is there something... wrong?" Sherlock remained quiet. "Did you have another fight with John?" Oh, yes, there it was. Embarrassment. Definitely another fight. She repressed a sigh and took off her globes, motioning Sherlock to sit down with her. "What happened?"

"I'm... not entirely sure." Sherlock furrowed his brows and looked down; re-analyzing step by step the argument, trying to find a clue of what he had missed.

Molly bit her lip. "Why don't you tell me the events that led to it, instead of the reason of the fight itself?"

Sherlock sighed with relief. That, he could do. He took Molly through it, explaining the evening in exact detail, and even throwing in John's facial expressions for good measure. He knew Molly didn't have the same level of intelligence as him, but she could be quite observant most of the time, and she was always a big help when it came to emotional matters.

When Sherlock finished, Molly took a few more seconds until her brain caught up with the explanation. She stifled a groan (and the urge to hit him over the head, while she was at it). How could a man so brilliant be so incredibly thick?

It was moments like this when Molly was grateful that her crush on him had dissipated...

"Sherlock, of course John is going to be mad. You lied to him. How would you have felt if the situation had been reversed?"

"That's ridiculous. John is a terrible liar. He could never fool me."

"I'm being hypothetical."

"But it doesn't make sense, how-"

"All right, fine." She bit her lip again. She had to think this carefully. Sherlock wasn't good with emotions, so she would have to find another way to get her point across. "Look at it this way, then. Your relationship is like..." Like what? She squeezed her brain trying to come up with an analogy Sherlock wouldn't classify as stupid, but could also be easy to grasp. She could feel Sherlock's eyes boring into her. He was probably getting impat- "Oh! Chemistry."

"What? In what context does 'your relationship is like Chemistry' make sense?"

"No, no. Sorry, that's not what I meant; but it's related to it."

"How could it possibly-"

"It's like an acid-base reaction." She smiled brightly at him.

"Oh, yes. Of course. I can't believe I missed it. John has been giving me protons all this time and I didn't even say thank you. No wonder he's mad at me."

"Oh, Sherlock, for God's- That's not what I meant!"

"Am I the one giving the protons, then? Because I can assure you I have never-"

"Do you want my help, or not?" She closed her eyes, fighting off the urge to smack him.

"How has any of this been even remotely helpful?"

"Fine, then. Good luck." She got up but was stopped by a hand on her wrist.

"Molly."

She sighed, but gave him a small smile, that was hesitantly returned.

"Hear me out, then. Imagine, hypothetically, that you are the base in this equation, and John is an acid." Sherlock looked like he was biting his tongue in an effort not to say anything derisive. "Acids give bases protons. Well, John does the same thing for you. In another way, of course. Since he met you, even before you two got together, he has given you his time, his companionship, his love. But most importantly, he has given you his trust. And you, being a base, don't give anything back. You just accept everything he gives to you, even the smallest thing, and you have managed to make them a part of yourself. But you've never reciprocated. I'm not saying you don't love him, because it's clear that you do, but... it's not a two way street if the other person doesn't know it."

"... May I talk now?"

"Go ahead."

"That was the most ridiculous and flawed analogy I have ever heard. Not to mention that if I actually reciprocated, it would stop being an acid-base reaction. But," His eyes softened. "I can see what you're trying to get at."

"Good. Don't duel too much on it, though. John knows how you are, and he loves you all the same, but... I'm sure he'd like to know that he can, in fact, trust you."

Sherlock merely nodded, already lost in his own head. Molly returned to the table to get her globes, hearing Sherlock leave behind her.

"By the way, your new neighbor does like you. He's just shy. Stop second guessing and talk to him."

"What?" She turned around, but Sherlock was already gone.

Author's notes:

Thanks so much to sleepyheadgish for editing this. You're a star ~

Also, I really hope I didn't screw this up. Chemistry is not my forte. At all. I did tons of research but I'm still afraid this is a complete fail, so feel free to bash on the coments if that's the case.

Still, hope you enjoy it (specially froggyk, as this is for you, dear 3)

Lots of love x