"Mary, I'm home!" John Watson entered the flat, feeling no small bit of pride. "We finally have Moriarty behind bars." He felt that there was something out of place. The lights were on, as usual, and the house was unusually quiet but...

And then it hit him like a train. The smell. The smell. It was repugnant, the tobacco smell in the room mixed with the scent of blood. He ran into the room, head swiveling from left to right. "Mary?! Mary, where are you?!" His voice was desperate. There were blood spatters walls of the kitchen, with objects thrown around the room. "Mary?!"

He found her body in the baby's room, her clothes ripped, her chest exposed with three knives in her bosom. He rushed forward, checking her pulse, even though he knew she was dead, trying to hold onto some vestige of hope for just a bit longer. He began to weep. "No..." His voice trembled. "No..."

He forced himself up. He had to take care of his son. He pulled himself to the cradle, and what he found forced all the air out of his lungs. His scream shook the room, his vocal cords strained, the torture done to them extremely painful, but he didn't care. His wife was dead, and the body of his infant lay in the cradle, mangled and sliced up, covered in bruises, cuts and blood, looking as if the corpse was tossed in there by whatever monster had done this. John bit his hand, blood seeping into his mouth as his canines and incisors sliced through his flesh. He felt the limp coming back. He collapsed. He needed his cane. No. he thought. He spoke aloud. "I need Sherlock." He called the sleuth over the phone. "Come on, come on..." He had waited from some time before Sherlock answered.

"Hello Jo-"

"No time for pleasantries. Get over here, now, or so help me, I will drag you over here behind my car."

There was a long silence before Sherlock answered him. "I'm on my way." His voice had lost all emotion, the voice he usually left for strangers, and the phone went silent. Watson leaned against the bed of the cradle, weeping lightly. Tears fell and hit the floor around him. "I'm so sorry, Mary... I'm so sorry..." Moriarty had promised that they would pay if he ever saw the inside of a cell or a coffin, and he hadn't been exaggerating. Watson wished they had never caught the mad man.
It was several minutes before Sherlock came in. "I came as soon as I could, John." He called from the door, his footsteps heard by John as he got up, walking stiffly towards the detective, knees, elbows, and back covered in the blood of his loved ones.

"Deduce who the assassin is and tell me who it is."

"John, what-"

"Mary and the baby are dead. Just tell me who the bastard is so I can find him and torture him to death." John's voice was hard and cruel, colder than Sherlock had ever heard it. Colder even than Sherlock at his darkest. He silent began taking in the details. He stepped into the baby's room and the details almost made him throw up. The baby, mangled up as if it had been swung around the room, into objects like the walls and furniture, as if used like a flail, and the evidence around him suggested as much. The knives in Mary's chest were ante-mortum, but happened after her neck had been snapped. It was the work of someone that Sherlock had hoped died in a fire ten years ago, from before he knew John Watson had even existed. The killer was a vicious man named Antonio Marquis. And Sherlock had no idea how to find him.