Sherlock received the news about Greg's arrival about as well as he expected... which was to say, not well at all. Even after Greg proved that his presence could be useful after all by questioning the owners of the pub, Sherlock continued to shoot him baleful looks out of the corner of his eye while he paced around the room in deep thought. He was acting exactly like a stroppy toddler and, as much as Greg hated to admit it, he was more amused by the behaviour than anything else. He drummed his fingers against the table, sipping idly at a cup of tea, and then glanced over at John. It didn't take a genius to realize that this case was clearly wearing on the both of them.

"How has he been?" he asked finally, tipping his chin in Sherlock's direction. Normally Sherlock hated leaving London, so he always made it a point to stay as close to the city as possible. Sherlock and the country did not mix. Greg had seen proof of that the last time he visited the family estate with both of the brothers. He still wasn't sure who'd been more out of their element, Sherlock or Mycroft, but either way it was a very close tie.

"Difficult," John said with a weary sigh. He looked tired, like he hadn't slept well. "This case is considerably more complicated than either of us expected."

Greg pursed his lips at that, intrigued. It wasn't very often that someone managed to stump Sherlock. The last person who'd done that was Moriarty, and he hoped to god the little psychopath wasn't involved in this because if he was then Greg was going to be having words with his mate. Angry words that would result in Mycroft sleeping on the sofa for the next two weeks. Tempting though it was to press John for details of that nature, he refrained. There was no sense in worrying him, even if he was sure that John had already contemplated that possibility. Instead, he drank the last of his now tepid tea and said hopefully, "Are you making any headway?"

"A bit, now that you're here to help smooth a few things over, but not nearly as much as Sherlock wants."

Reflexively Greg glanced around for the detective and realized that the rest of the pub was empty. Either Sherlock had thought of a new lead and run off, which was unlikely considering John was still sitting across from him, or he'd got bored with pacing the small room and moved on to a larger space. "I know he's pissed that Mycroft asked me to come down," he admitted. There didn't seem to be any point in continuing to pretend that he'd decided to wander down of his own free will. Sherlock wasn't the only one who rarely left London.

John shot him a small smile. "Actually, I think he's pleased that you're here. Not that he'd ever be willing to admit it, but Sherlock likes it when you're around. Though I'm not sure if it's you he likes or the fact that, by having you here, he's keeping you away from Mycroft."

"That sounds about right," Greg said, rolling his eyes. Sometimes he felt a bit like a favoured toy. He jumped at the sound of a clatter and looked around to see that Sherlock had set a cup of coffee down on the table. Even as Greg watched, one eyebrow raised, the detective slid it across until it was sitting in front of him.

"Sherlock," John said.

"I made you coffee," Sherlock said, ignoring John.

Greg looked down at the cup. "Did you now."

"Sherlock," John said again, more firmly this time. "We talked about this last night."

"You got to do it. I don't see why -"

"Oh for god's sake." Heaving another, far more exasperated sigh, John grabbed the cup and stood up. He marched behind the bar and dumped it into the sink. Sherlock scowled and started to protest, but apparently John wasn't in the mood to hear it. He returned to the table, grabbed Sherlock by the arm and physically hauled him to his feet. Greg had to bite back a laugh as they walked out of the pub together like they didn't even remember that he was there. They were glaring at each other in a way that meant they were having a silent argument, and he was just as glad he couldn't hear it.

He took out his phone. "I think your brother just tried to drug me," he said by way of greeting.

Mycroft's sigh was perfectly audible even over the line. "That does sound like something Sherlock would do, yes. Since you say he tried, I'm guessing Doctor Watson stopped him."

"Should I be insulted that you automatically think John stopped him instead of me realizing what Sherlock was doing?"

"Gregory, even after all this time and the many ways he's proved he does not deserve it, you still have an inherent trust in my brother that I will never understand. No matter how often I tell you not to accept food or drink from Sherlock, you still do it." Mycroft paused, and when he spoke again his voice was considerably softer. "It is one of the many things I admire about you."

Suddenly Greg was glad that Sherlock and John had departed, if only because he was pretty sure he was now blushing. He shifted uncomfortably, clearing his throat. "Thanks," he muttered. "So, look, Sherlock seems to be pretty rattled about this case. I haven't seen him like this for a while."

"It's complicated," Mycroft said, thankfully accepting the change in subject without protest.

"Complicated in a guns are going to be fired soon sort of way?" Greg asked. He was conscious of the weight of the gun at his hip, since he rarely wore one. Mycroft had given it to him right before he left. He'd intended to leave it in his suitcase, and it didn't bode well that he didn't feel comfortable enough to do so.

The pause was considerably longer this time. "Perhaps."

"Bloody fantastic." He got up and left the pub, heading up to his room. "They just left now. I won't follow, but let me know if Sherlock starts trying to get himself killed."

Mycroft agreed and they hung up as Greg reached the door to his room. He actually didn't have that much to do, but following Sherlock and John around wouldn't do much good either. Sherlock would know he was there and it would only serve to make him feel like he was being monitored by Mycroft, which never did much to improve Sherlock's concentration. In the end, he lay down on the – surprisingly comfortable – single bed and fell asleep.

He woke up to his phone and Mycroft's alarmed voice telling him to get out to the moor immediately, and later Greg would almost wish that he'd slept right through the call because he could've done without seeing that hound. The night air was cold and felt like it was sinking right through him as he and John shone their torches up at the dog, catching the gleaming red eyes and long white teeth. He stumbled backwards as the hound leapt down the hill towards them and swore.

"What the hell is that?" he shouted.

"Sherlock," John was saying, voice trembling.

"Henry! It's not – it's here, but it's not real, oh god, it's the fog, it's drugged us!" Sherlock was trying to focus, but Greg could hear him panting, low and frightened, and it was enough to make a surge of protectiveness cut through the fear.

He drew the gun that Mycroft had given him and fired once, twice, three times. The sound jolted John and he pulled out his own gun. Between the two of them, they hit the hound twice. It staggered, growling, and Greg fired again. This time it went down, sprawling in a twitching heap. Greg was gasping, felt like he couldn't breathe properly, too much happening in too short a span of time, but the handle of his gun was hot and sweaty and real and he strode closer impulsively to put the last of his bullets in the creature's head.