Sherlock and John wandered around the flat.
"There has to be something, Sherlock." John said, frustrated. "There must be something about him that may indicate where he is."
Sherlock held his head with his hands. "There is nothing, John." He said. "He could be anywhere around London."
"What are we supposed to do then?" John asked. "This girl must be terrified. She don't know what had happened or where is she. And she is held by a maniac."
"I don't know what he want me to do." Said Sherlock. "I have no lead whatsoever."
"Find one!" John said, angry.
Sherlock opened his mouth to reply when there was a knock on the door. He glimpsed to the clock. It was almost one a.m. Who could be visiting at such an hour?
When he opened the door Mycroft stood there, holding something in his hand.
"What do you want, Mycroft?" He asked impatiently.
"I need your help."
The mere words took Sherlock by surprise, and he could easily see Mycroft was just as surprised as him.
"It's not a good time." Sherlock said. "I'm on a case."
"Is that a matter of life and death?" Mycroft asked. "Because that is."
"Yes," said Sherlock, irritated, "it is a matter of life and death."
He was about to close the door when Mycroft spoke again.
"It's concerning the reason I was at the hospital today." He said, clearly annoyed from the need to use that card.
Sherlock hesitated for a second. On the one hand, Mycroft was offering telling him what he wanted to know all day long. On the other hand, there was a riddle from Moriarty he needed solve.
"Sherlock!" John called suddenly. "There's another call."
In an instant, Sherlock decided.
"Come in," he told Mycroft, "and be quite."
They walked to the kitchen where John sat. As he saw them, he pressed the 'answer' button.
"Hello?" He said.
"Hello, John." They all heard it. The voice that came out of that phone wasn't the girl again. It was Jim Moriarty himself speaking to them. "Have you solved my puzzle yet?"
"Where's the girl?" John asked.
"Not as cooperative as earlier." Moriarty replied.
John and Sherlock switched quick glimpses. "Is she..."
"Alive. That is all you need to know."
John's voice was confident. "I want prove."
"Prove, yes." Said Moriarty. "Come, dear. Let's give these men prove."
There was a struggle and a short high-pitched scream and then the girl returned to the phone.
"Say something." They could hear Moriarty saying in the background.
"Go to hell." The woman said and Moriarty pulled her off the phone once again.
"Prove enough?" He asked.
"Yes." Said John.
"By the way, I've been wondering, has Mycroft arrived yet?"
Sherlock looked at his brother. All conversation long he was out of focus, but to the sound of the female voice his focus returned. He dropped what he was holding in his hand, and leaned on the table in order not to fall down.
"Yes," Said John, "he's here."
Moriarty said "how exciting" and hung up.
"What is it?" The detective asked his brother. "What had happened?"
"It's my fault. It's all my fault." Mycroft said, his head in his hands.
John lifted the object off the floor. "It's a wig." He said.
"Mycroft." Sherlock said, his voice steady. "What do you know? It might be a matter of life and death."
Mycroft lifted his look to Sherlock's eyes. "It is a matter of life and death," he said, "And it's all my fault." He took a deep breath and started talking.
"I was at the hospital today not alone. I was with a girl, a woman." Mycroft sighed. "But you knew that already. I invited her to dinner last night, she agreed."
"You had a date?" Asked John, amazed.
"No, it was nothing like this." Mycroft seemed irritated that John didn't understand. "She... I knew her mother."
"Knew?" The word hadn't slipped from Sherlock's ears.
"Dead. I'm the only family the girl have. On dinner we relived an argument that started right after her mother's passing. We fought, I left. Came back to apologize and," he lowered his look to the wig in John's hand, "she was gone. I found the wig on the pavement and knew there was something wrong."
"How?" John asked.
"She hated the wig, yes, but she never took it off where people might see her. There's no way it was on the ground because she agreed to it."
But Sherlock was not listening. "We must know everything about her if we'd like to save her." He said, wandering around. "She's the key to her own rescue. What type of cancer did she have?"
"Leukemia."
Sherlock stopped. "Did she get a bone narrow donation?"
Mycroft hesitated.
"It might be important," Sherlock said.
"Yes." Mycroft finally said.
"From whom?" Sherlock asked. "She had no family, the chances of-"
"She did," John said. "Had family, that is. Didn't she, Mycroft?"
"Mycroft," Sherlock said, "did you give her the bone narrow?" Mycroft hadn't replied, and Sherlock continued. "You did, didn't you?"
"I was a match." Mycroft said. "A perfect match. Do you know the odds? What was I to do, let her die? Yes, I gave her the bone narrow donation."
"You have a daughter?"
"No." Mycroft said, frustrated. "I'm not the father."
"You spoke of odds? Well, the odds of a non-family related donor, especially one who was acquainted to the patient is so small that it's impossible." Sherlock said.
"Sherlock." John said.
"So you must be family related to her, there's no other option." Sherlock continued, ignoring John.
"I am family related to her," said Mycroft. "Just not get father."
"Who is her father then?"
"Sherlock." John said. "Take a look."
"What?" Sherlock said, irritated. He came to John and looked at the wig. In it was a writing: 'Belonging of Sher A. Lucas.'
"Sher." Said John in disbelief. "Her mother actually named her Sher."
"Yes, Jenna had always been a bit sentimental," Mycroft said.
"She's..." Sherlock was shocked. "I'm..."
"I told you, Sherlock. Sher is not my daughter." Mycroft said, looking at his brother. "She's yours."