Sherlock frantically waved down a taxi, yanking the door open and hurling himself in before the cab had even come to a stop. He shouted the address of Moriarty's building at the driver and promised him double fare if he drove as fast as he could, then sent a hurried text to John as he hurtled off to save Molly.
Found Molly. Texted you address. Bring your gun. – SH
John's reply was almost instant.
On my way. Don't get yourself killed before I find you.
Sherlock's mouthed twitched as if to smile, but the expression never graced his lips as he remembered his last call with Moriarty. He urged that cabbie faster.
Twenty seven minutes and twelve agonizing seconds later, the cab rolled to a hasty stop outside Moriarty's building. Sherlock threw a handful of notes into the front seat and raced off to find his pathologist. Inside the building, the corridors were dimly lit, and he only just saw the boy in time to not run into him. The boy that Sherlock noticed had been kicked out of his home, the silent one that followed Danni, stood in the hallway.
"You?" Sherlock asked, momentarily distracted. The boy simply nodded and pointed to the elevator door.
"Stairs are rotten. Basement level, cell nine. She's hurt pretty bad. Don't know where he is." He said, then scurried away as Sherlock bolted for the elevator. He punched the button for the basement level before he was even all the way into the elevator, and the rusty doors slid shut.
He texted John where to find him and shook himself, readying for whatever attack would come when the doors grated open again. He tensed. The doors opened, and Sherlock was met with an empty hallway.
Cautiously, he stepped out, drawing his own gun and a pocket sized torch, shining it ahead of him. The beam glinted as it hit a number on the door closest to Sherlock. Number 1. The door had a hole at eye level cut into it, barred with metal poles set into the two inch thick metal of the door. Sherlock approached the door and directed the torchlight through the bars. The room was a cell, complete with a bucket to relieve oneself in, manacles chained to the wall and a soiled mattress. The cell was empty.
Sherlock withdrew and began pacing down the corridor, searching for cell 9. When he had reached cell 7, a whimpering voice reached his ears that he would recognise anywhere. Molly.
Sherlock ran toward the sound, coming to a stop outside the only cell lit with a bare bulb hanging from the ceiling. Through the bars, Sherlock glimpsed a naked figure covered in bloody injuries tied to a chair in the centre of the room. The mousy brown hair was matted with blood and covered her face, but Sherlock recognised his pathologist as she shuddered and sobbed. He quickly checked that she was alone before picking the lock on the door and throwing it open, making her cower in her chair at the sound of someone approaching.
He knelt in front of her, untying her wrists and ankles as he spoke quietly to her.
"Molly? Molly, I'm here. It's Sherlock, I'm here. I'm going to get you out of here, Molly. John and Lestrade are on their way." He murmured, smiling in spite of their situation as Molly raised her head and looked into his face with a mix of sadness, relief and joy. Her tears continued to fall as Sherlock pulled off his Belstaff, helping her to push her arms into the sleeves and secure it around her. The he hoisted her into his arms and tucked his gun inside his suit jacket, carrying her out of the cell and stopping short in the corridor.
"Look who finally decided to join the party Molls! Its your knight in shining armour, but I must say, you looked better in my shirt than you do in his coat. Much less sexy, don't you think, Sherlock?" Moriarty asked, his gun aimed at Sherlock's head.
"Enough, Jim. It's over. No more games." Sherlock replied, his voice steely and cold. He tightened his grip on Molly as she shied away into his chest.
"Oh but Sherlock, the game is only just getting started. Molly here was the appetiser, but I'm still hungry. I think it's time for the main course, don't you?" Sherlock stood defiantly, staring at Moriarty as the villain readied his weapon to shoot the detective.
"I'm bored with you, Sherl. I thought you were more than this. Molly was a much better plaything. You should have seen her, she-" Moriarty was cut off with two simultaneous gunshots. As Molly had stolen Sherlock's gun and shot Moriarty in the chest, John had appeared behind Moriarty and shot him in the head. His body fell to the floor and Lestrade rushed forward to take his gun and confirm him dead, while Sherlock gently coaxed the gun away from Molly.
John rushed forward and began checking Molly's injuries, and to Sherlock's surprise, Mycroft appeared moments later with a private medical team that helped Sherlock carry her outside to an ambulance. Sherlock took a moment away from Molly's side to speak to his brother, and it was arranged that the medical team would set her up to be treated at 221b, where Sherlock could watch over her.