Around 9 p.m., Sherlock finally arrived at the bar Molly had spoken of, and as it turned out, some of the hospital staff and Greg were in attendance. Sherlock couldn't help but roll his eyes when he saw the Detective Inspector sitting in front of him. And the DI looked slightly taken aback as well.

"Sherlock, what are you doing here? Are you lost or is some case driving you here?" he then asked, looking at him with curious eyes.

"No, Detective Inspector. To be honest, Molly invited me" he replied coolly, literally spitting out the words Detective Inspector.

Greg just nodded knowingly and then turned to his beer in front of him. Sherlock felt all the eyes at the table on him once again. But he didn't care. What mattered was Molly and that she would tell him who was behind the news.

Molly also seemed to sense this curiosity for a certain detective and how the mood at the table was starting to change. So, to be polite and as she had been taught, she decided to introduce Sherlock to everyone. Sherlock himself had no great interest in knowing the names of everyone present, but for Molly's sake he let the introductions slide. It was in her nature to be friendly and polite. But what surprised him a bit was when Molly introduced a particular person and her facial expression changed.

"And this is CARTER, he's been working down at the morgue for a while now, helping me with my autopsies."

Sherlock knew something was off about this Carter. Was he this mysterious letter writer?

Molly finished the round of introductions and then turned back to her colleagues. Not without glancing again at Sherlock to see if he understood. He nodded only slightly and then turned his attention to this Carter. Contrary to his nature, he joined in the conversations of those present with feigned interest. He chatted at length with Molly's colleagues, meanwhile learning about his time in the U.S. or how he and Tom met. Sherlock was actually heartily uninterested in his life but he was eager to find out if this Carter was behind these messages and continued to feign curiosity.

The evening wore on and Sherlock had been listening to Molly's colleagues for hours. So far he couldn't see or hear anything unusual about him, but there had to be something and Sherlock was sure he had to find out as soon as possible. His opportunity came when Carter excused himself and headed for the restroom.

Sherlock followed him at a short distance and then waited on the door in front of him. As he waited there like that, he remembered the last time he had been here. It was the same hallway where Sherlock and Molly stood leaning against the wall, smooching wildly. The same hallway where Sherlock felt that Molly was so much more to him and that he wanted her. Just her. A slight smile played around the corners of his mouth as he thought about it and the places where Molly touched him tingled.

The feeling and smile disappeared, however, when Carter stepped back out the door. Without thinking about it, he grabbed him by the collar and shoved him hard against the wall.

"Whoah, buddy. What's gotten into you?" asked Carter, slightly confused and with a hint of fear in his voice.

"I know those messages are from you. So what do you want?" growled Sherlock back at him.

"What messages? I've only known you since tonight. So why would I write you any letters?"

Sherlock tightened his grip and Carter whimpered slightly at the pressure around his neck.

"Interesting. I don't think I told you they were letters. So what do you want?"

Carter knew he was busted, but decided not to act on it.

"You're out of your mind! I don't want anything from you and now let me go!" he growled now as well.

But Sherlock didn't respond. Instead, he just grabbed him tighter and now lifted him slightly off the ground by his collar. In front of him stood the author of these messages, he knew that. He just had to get him to talk.

"So, I'm going to ask you one more time. What do you want?"

Carter whimpered and squirmed under his grip. So slowly he seemed to sense that there was no escape and his air was running out. If he didn't do something quickly, he was going to die here.

"Okay, okay, okay," he then whimpered and raised his hands in surrender.

"I wrote the letters but I had to do it".

Gradually it dawned on Sherlock and he slowly set him back down on the floor. His grip on Carter's collar, however, he still maintained.

"You should know you're being watched" he whispered softly now, leaning forward a little.

"Aaargh! I know that too. So who's your employer?" growled Sherlock, looking at him with a slightly menacing look.

But before Carter could speak, they were interrupted by an approaching voice at the front of the hallway.

"Hey Carter! Where you at, man?"

It was another colleague from the hospital. He slowly approached the two and then put a hand on his friend's shoulder to lead him back into the guest room.

"Come on. We want to move on." the man said.

"I'll...I'll be right there," Carter stammered lightly as he saw the penetrating look on Sherlock's face. Then he turned slowly and followed his friend back. Sherlock stopped him as he also placed a hand on his shoulder.

"This isn't over yet" he then said and subsequently released his shoulder.

Back in the guest room, he noticed that everyone was already slowly getting ready to leave the bar. Only Greg was still sitting at the table, sipping his beer.

Sherlock was also getting ready to leave the pub when a gentle touch on his arm stopped him.

"Is everything okay?" asked Molly, slightly nervous.

"I have to go now" he replied emotionlessly, releasing himself from her grip.

Without saying goodbye, he stormed out of the diner. Out into the cold and dark night.

In his head only one question:

Who is it?