Sherlock was stunned. "His sister," he said. "You're his sister."
"Well done," she said.
"What?" John could barely believe what he was hearing. "All this time you've been trying to kill me? Nina, what?"
"Christa, please. But I haven't been trying to kill you. My brother has. I've just been helping him."
"What's been bothering me," interrupted Sherlock. "Is why he hasn't done it yet."
Christa smiled at him pityingly. "I'm not going to tell you that."
Sherlock was afraid, but he wouldn't let it show. He had no direct route to Moran except for this woman, and she wouldn't tell him anything. Moran was more difficult to track than Moriarty had been, because Moriarty had liked games, just as Sherlock did. He hadn't been able to help himself, and he'd created pathways, riddles and plot twists just to bring Sherlock to one place, at one time, with the same result as what could have been achieved in the beginning, without all the extra steps. Moran was more interested in the end than the path it took to get there. He wasn't one to seek after an audience. He would strike hard and fast and with ultimate accuracy. He wasn't going to bother with creating vast webs of complex patterning. Sherlock would have nothing to go on, no links to follow. Nothing. And he knew it.
And even though his doubts were overwhelming, Sherlock spat his words in her face. "He will never get to John."
Her answering smile told him everything he needed to know. "Save your lies for someone who's gullible enough to believe them."
His chest stopped for a moment. "John, the router. To Lestrade, now. And then bring him back here. There's someone here who needs to spend a long time in prison."
"Oh… Right… Yes… Sorry…" John stuttered, and he left quickly, his feet thumping up the stairs.
Christa flashed her teeth at Sherlock as she laughed hoarsely. "You really should go with him. "Never know when Sebastian will attack."
Sherlock's eyes flickered between each of hers. "He's safe for now," he said. "Your brother wouldn't risk it whilst you're under threat."
"You really don't know anything, do you?" She threw her head back bitterly. "He would not care in the slightest if you were to kill me. He doesn't care about anything, never has. He's ruthless. He'd kill me himself if he ever had a reason. Which he does now, because I've failed him."
"Then tell me why he wants John dead, if you're going to die anyway," requested Sherlock.
"I don't think so," she said. "This isn't a game, Sherlock Holmes. This is real. He doesn't want to play like Moriarty, he wants to keep his plans a secret. Not like Jim. Jim was stupid. But my brother, he is cleverer than you know. And you'll never beat him because he doesn't work like you do. He's much more like John. Straightforward, without all the fancy loopholes. It's the same reason as to why you can't understand your own boyfriend."
"I know John," Sherlock objected.
She pushed herself into the tall man. "But you can't read him. You never know what's going through his head. You can't tell me that you know exactly how John thinks, because it would be the greatest lie anyone could possibly tell."
Sherlock couldn't say anything.
"But there is one big difference between my brother and your boyfriend," Christa whispered. "John feels. And that is not an advantage, Sherlock. It makes him weak. John could be so much more, but he chooses to have emotions. What a shame for you, considering that will be the thing that kills him."
Sherlock's arm released her neck entirely, and she beamed in satisfaction. Until his hand came around her waist to snap her spine at the small of her back with a deafening crack.
Her scream was filled with blood.
Lestrade burst into 221C with a pair of handcuffs at the ready. But what he saw, Sherlock standing over the battered, wrecked body of the young woman he had come to arrest, stopped him in his tracks.
"Don't worry, Lestrade," Sherlock said gravely, not turning to look at him, but staring down at Christa with burning hatred. "She's not dead. I'm sure she'd appreciate an ambulance, though."
"Sherlock," Lestrade gawped. "What have you done?"
"Shut up, Lestrade. I need to think."
"No, Sherlock!" Lestrade exclaimed. "No! This isn't acceptable. You've gone too far this time. No. This isn't right. I can't let you go after this. Right, I'm arresting you."
"Lestrade," Sherlock said calmly. "Please. John's life is in danger and I'm the only one who has a chance at stopping it. This woman is Sebastian Moran's sister, and she has been sending information through to him for years. This is only about John's safety."
Lestrade shuffled anxiously. "That gives you no right to beat her almost to death. You're coming with me to the station."
"I'm really not," Sherlock said scornfully. "It's John's life that's at stake, and I'm not going to waste my time at Scotland Yard when I could be figuring out how I can save him."
Lestrade was stuck. "I can't let you go free, Sherlock. This is a criminal offense."
"She deserved it."
"That doesn't matter!" Lestrade was shocked at him. "Look, you can either come willingly or I'll put these on you." He waved the handcuffs at him. "But I'm not letting you out of this one."
Sherlock paused a moment. "Fine, I'll come. But only so I can have a look at the results for the router analysis."
Lestrade sighed, but allowed Sherlock to pass by him and leave the flat to go sit in the car. Then he pulled his phone out of his pocket and rang for an ambulance, scrutinising the young woman's body as he did so. Barely a bone was unbroken and the snapping of her spine would leave her paralysed from the waist down. He let out a long breath. Sherlock had gone too far.
The woman on the other end of the line picked up, so he told her the address and all of the injuries that were visible to him on the body. "What happened to her?" the woman asked eventually.
Lestrade thought on his feet. "She was hit by a bus," he said, then he picked up the unconscious Moran and carried her out onto the road.
"Stop the next bus," he commanded to the officers who were still assembled outside as he placed Christa onto the road. "Just here. Don't say anything to anyone. Got it?" They nodded and hurried to the end of the road to wait for the bus.
The detective looked over to his car, where Sherlock's face was visible through the windscreen. He gave a slight nod, which Sherlock seemed to ignore, but there was a slight contraction in the muscles at the side of his mouth.