Author's Note: Happy New Year everyone! I know this chapter isn't very long, but I really wanted to get it out today. So I hope you don't mind that it's a little bit shorter than usual. The next instalment is on its way very soon!

III

In the weeks that followed Mary's death, Sherlock had traded his crisp neat shirts for dressing gowns, replaced sunlight with the darkness of his flat, fresh air for dust. His skin was sullen, his jaw coated in stubble, his hair falling in greasy curls over his forehead. He was a problem solver – a fixer. But Mary's death wasn't one of his cases. There was no solution that would bring her back, no way to fix everyone's suffering. His frayed relationship with John wasn't a case that could be solved, and it was driving him mad. He turned a piece of yellowed paper in his slender fingers, glancing over the words scrawled across it.

I need to kill someone.

Who?

But he wasn't looking at the words.

As he regarded the mousy-blonde, spectacled woman in front of him, deductions intruded on his thinking. They were like reflexes; involuntary, and not always welcome. He paced the living room of his flat, spouting information – everything from her sex life to the size of her kitchen. All from a single piece of paper and her long red dress.

His hands began to shake. He clenched his fist tightly and made his way to the kitchen, dismissing the woman as she pleaded with him to take her case. He picked up her handbag and threw it at her, noticing the weight of it as it left his hands. He slid open the glass door revealing Bill Wiggins sitting at the kitchen table in front of a bubbling drug lab.

"Please," she said desperately. "I have no one else to turn to."

"Yes, but I'm very busy at the moment and I have to drink a cup of tea."

Bill watched as Sherlock walked to the table and picked up a teacup full of syringes, carrying it to the kettle. "This cup of tea… Code?"

"it's a cup of tea," Sherlock snapped, emptying out the syringes on the counter.

"You're my last hope," the woman called from the living room.

"Really?" he replied uninterestedly. "That's bad luck, isn't it? Goodnight, go away."

He slid the door closed.

"What's bad luck?" asked Bill.

"Stop. Talking. It makes me aware of your existence."

Bill ignored him. Continuing to talk as Sherlock made his way back to the counter.

Suddenly, a thought hit him. A deduction that had taken a moment to click, like a delayed reaction.

"Handbag," he said.

He hurried downstairs, relieved to see her at the front door. Her hair and shoulders were damp from the rain, yet she hadn't brought a coat. The mark on her dress indicated she travelled by taxi, yet she hadn't called one to pick her up. While one hand held a walking cane, the other periodically pulled down at her sleeve to hide scars on her forearm. And her handbag – Sherlock knew – contained nothing but a handgun.

Losing Mary had made him realise that death didn't just take life away from the dead. Death, he had learned, took life from those left behind. His hands were shaking, his mouth dry, his eyes itching, but he couldn't let her leave. He couldn't allow another death on his watch. And so he reluctantly took off his dressing gown and replaced it with his coat.

Mrs Hudson opened her door and stepped out into the hall.

"Sherlock!? Are you going out!?"

"I think I remember the way, it's through there, isn't it?" He sniffed sharply as he spoke, his head swaying as if it weighed a ton.

"Oh, you're in no state, look at you!" she cried.

"Yeah well, I've got a friend with me, so…"

"What friend?"

Pouring rain pelted the pavement. She watched him helplessly as he stepped out into the night.

"Bye." He slammed the door.

Mrs Hudson let out a worried cry as she hurried back inside her flat. She picked up her phone and waited anxiously, biting her finger and tapping her foot.

"Margaux? Oh, Margaux… he's bad."

A sigh melted through the phone.

III

John sat quietly in his living room while Rosie slept upstairs. He kept the television on mute; partly because he didn't want to risk waking his daughter, but mostly because he could see his wife standing in the doorway.

His phone began to ring. He glanced at it before looking back to Mary.

"You should answer it," she said.

"It's Mycroft," he replied.

"Might be about Sherlock."

"Of course it's about Sherlock, everything's about Sherlock."

He stood up, holding the phone is his hand with his thumb hovering over the 'decline' button.

Mary folded her arms. "You know, just because I'm a figment of your imagination doesn't mean I won't kick your arse."

John laughed quietly before slipping the phone into his pocket and making his way to bed.

By the time he had climbed the stairs, checked on Rosie and brushed his teeth, John had missed four more calls from Mycroft. Finally, on the fifth, he answered.

"I'm trying to sleep and you're still ringing my damn phone."

"Sherlock has left his flat. First time in a week. So I'm having him tracked."

"Nice," he replied sarcastically. "It's very touching how you can hijack the machinery of the state to look after your own family. Can I go to sleep now?"

"Sherlock gone rogue is a legitimate security concern. The fact that I'm his brother changes absolutely nothing. It didn't the last time and I assure you it won't with…"

John furrowed his brow, holding the phone firmly to his ear.

"With Sherlock," Mycroft finished.

"I'm sorry, what?"

"Please phone me if he gets in contact. Thank you."

John hung up the phone and placed it on the bed beside him. he thought for a moment. 'The last time', Mycroft had said. 'It didn't the last time and it won't with Sherlock'.

III

Sherlock lay on the couch with his hands by his sides. He was so still, he could be mistaken for a corpse if it wasn't for the heavy breaths escaping his open mouth. The woman with the cane. It had been two days since his night with her, and yet he couldn't stop thinking about it. The case she had brought to him, the things they had talked about as they walked around London, the last thing she said to him before he passed out.

You're not what I expected. You're… nicer.

A gush of cold water against his face jolted him awake. His eyes burned red against blue as he looked up, panting in shock.

"You were supposed to see your son today. But something told me not to bring him," said Margaux as she stood over him, an empty glass in her hand.

"Mother's intuition?" he replied sarcastically.

"Call it the power of deduction." She folded her arms. "One of your best friends died, John isn't talking to you and you're in turmoil over a case – I can tell. I haven't seen you in days, you've been inactive online, you haven't been turning up at my work to butt in, and then Mrs Hudson calls to tell me you went off gallivanting around London with a mysterious young woman…"

He dragged himself upright, his head swaying, eyes opening and closing slowly.

"Don't have to be Sherlock Holmes to know that you're using again," she said, her soft voice laced with anger.

He looked up at her and blinked rapidly. "Ah, Margaux, when did you get here?"

She laughed in disbelief.

"I told you he was bad," said Mrs Hudson from the doorway of 221B.

"Yeah, not half," she replied.

Sherlock stood up and pulled a gun from the pocket of his dressing gown before scratching his head with it. Margaux and Mrs Hudson jumped back in alarm.

"Sherlock!"

"Oh, give it a rest, Margaux. Blah blah blah blah blah," he said as he wandered unsteadily into the kitchen.

Margaux followed him, watching in disbelief as he pushed up his sleeve and began to tie a tourniquet around his arm.

She turned to Mrs Hudson calmly. "Can you give us a moment?"

"Of course," she replied worriedly before returning downstairs.

"Sherlock…" Margaux began through gritted teeth.

He handed her the gun. "Can you hold this?"

She took it from him, almost bewildered and not knowing what else to do. "Sherlock. You're killing yourself."

"Thank you, Doctor. Oh wait, not that kind of doctor."

"I can't stand here and watch you do this. Our child doesn't deserve this."

"This isn't about Vaughan–"

"No. That's the point. You're not thinking about him at all!"

"Yes, recent events have caused me to have somewhat of a one-track mind."

"You," she growled, pointing her finger at him. "You are not the only one who lost her, alright!? We all lost her and we all miss her. Stop being so bloody selfish."

He pulled the tourniquet tight with his teeth. "Of course. I'm awfully sorry that I'm not behaving as well as you think I should be. My deepest apologies for doing something to somewhat help me cope–"

"Grow up. We all know this isn't about coping. This is you having a tantrum because you're not getting your own way; because John won't talk to you so you've decided to self-destruct instead. It's ridiculous!"

He ignored her, lifting a syringe to his arm.

"Sherlock," she breathed slowly, the air shaking as it left her lips. "If you inject that, I'm done. I mean it. If you put that in your body, I am gone – I am walking out and I am never coming back..."

He looked at her with bloodshot eyes. Was she serious? A part of him felt fear at the prospect of her threat. But the other part was overwhelmed with curiosity. He was Sherlock Holmes and he never passed up the opportunity of an experiment – the chance to test a theory.

So, he pushed the needle through his skin.

Margaux let out a scream and fired a shot into the ceiling. Sherlock instinctively ducked and threw his arms over his head, stunned by the loud noise and the plaster that snowed down from the hole in the ceiling. He looked up at her slowly with wide, confused eyes.

She put the gun on the table and took a step back.

"Done," she said firmly, before walking out of the flat.