A/N Hey ya'll, I got a new chapter! Thanks for making it this far, I'm glad you've stuck with me ^_^ Also, sorry I took so long to update. I was getting over being ill then got struck with a major case of writer's block (ugh). This chapter was a real struggle to squeeze out of me. But now, cases with mutants begin!

Two weeks after Agent Coulson had stopped by and recruited Sherlock, John found the detective continuing to add the the makeshift evidence board that was still hung up on the wall above the couch. The stroppy detective had been waiting for a new case and nothing had arisen, leading him to fall into one of his bad moods. Not a whole lot of new information had come up regarding the Michelson case and the trail had gone cold; the fact that it was unsolved aggravated the detective every day.

John was reaching his limit listening to Sherlock complain when Lestrade stopped by with a case to save the day.

There was a murder in South London and it looked anything but normal. Sherlock, John, and Lestrade sat in 221B examining photos of the crime scene. "When we showed up the dust stirred, erasing what little strange evidence we did have," Lestrade explained. He handed Sherlock a picture. "But we managed to snap a few pictures."

The victim was lying face down on the floor with evidence of a scuffle around him. To and from the body, imprinted in the dust and dirt, were footprints. The other photos went to show that the footprints led to and from a large mirror on the wall.

"Victim's name was Evan Warren. Locked room," said Lestrade, "no signs of forced entry and there were no windows." Sherlock continued to flip through the pictures. "What do you make of it?"

Sherlock slapped down the photographs. "I take it the body's been taken to the morgue."

"It has."

Sherlock stood and walked over to the hook which he jacket hung. Along the way he shrugged off his robe and it landed soundlessly on the floor. "I'll head over to examine it now – don't feel the need to follow." Tugging his jacket on he looked over to John and jerked his head to the door. "Let's take a look at that body."

-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-

It didn't take much convincing to get Molly to let the detective and blogger have a look at the body. The pathologist pulled back the cloth over the body and Sherlock instantly got to work.

Cause of death: Knife wound to throat

Owner of two cats

Recently divorced

Works indoors (desk job)

Icosahedron tattoo

Sherlock halted and stared at the victim's left arm. "John…"

The doctor looked over and froze. "It's the same symbol."

"What, so he's connected to the Michelson murder?" John questioned.

"He's related somehow." He pointed to where the tattoo was placed – which was the inner-forearm. "This tattoo is in the same part of the body as Garret Vales."

"What, the man who died in the car accident a while back?"

"That's the one." The duo stared at the body for a few moments longer. "I need to find what this symbol represents," Sherlock determined, "it's the keystone to the problem. Once I figure out what it means everything else should fall into place." He turned and quickly walked to the door.

John began to follow before calling out behind him," Thank you, Molly."

The pathologist shook her head. "No problem…"

-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-

The next day John found Sherlock continuing to stare at the evidence board on the wall (to which the new photographs had been added). The blogger picked up the news article lying on the table. The headline read: Mysterious locked room murder! A killer that can walk through walls?

John held up the paper for Sherlock to see. "You take a look at this?" he questioned.

Sherlock briefly glanced over his shoulder then went back to his work. "Yes, the papers do always seem to exaggerate, don't they?"

John set the paper down on the table again. "Well, maybe they aren't exaggerating – well, unknowingly. Who knows? Maybe this killer really can walk through walls."

There was a long silence between the two and for a while John had simply concluded the detective had ignored him. Then Sherlock turned around. "John, you're brilliant."

"Hm?"

Sherlock dashed to the photographs of the latest crime and took them down from the wall and examined them closely. "The footprints, John. There's no doubt the killer was a mutant – the chances they weren't are extremely low – so it's quite likely they used their abilities to commit the crime." He walked quickly over to his flatmate and pointed the photos. "The footprints, look at the footprints!"

John took the picture from Sherlock's hand and his eyes skimmed over it. "They're to and from the mirror…" He raised an eyebrow at the detective. "You aren't seriously suggesting–"

"I was hardly the one who suggested it John," Sherlock pointed out, gesturing to the newspaper.

The sound of thudding footsteps on the staircase caused both men to turn. Lestrade soon stood in the doorway. "There's been a second killing," Sherlock said, before the DI could speak. Lestrade simply nodded. "And it was exactly the same?"

"Yes."

"Identical?"

"Of course."

"Did he have the same tattoo as the last victim?"

"Yes."

"We're the footprints just as the last murder?"

"What?"

"The footprints, Lestrade!"

"Er, yeah," he said. "Yeah, the only sign of someone else in the room was near the body and a mirror."

Sherlock clapped his hands together and grinned manically. "Yes! Perfect!" He took the photos back from John and headed over to the evidence board and began pinning them up again. "I won't be needing to take at the crime scene, Inspector, I've nearly figured it out."

Lestrade nodded slowly. "Right…" He cleared his throat. "In that case I'll be off. Sent me a message when you've got it, yeah?"

"Of course."

Lestrade gave John a smile and went back out of the flat. John turned to his flatmate. "You've nearly figured it out?" he questioned.

Sherlock was looking back and forth between his evidence wall and the fireplace. "Yes, of course. Didn't you hear me?" He rushed over to the fireplace and began readjusting the mirror that hung over it. He looked over his shoulder, trying to find the right angle. "I suspect we'll have the killer soon."

"You do?" John asked.

Sherlock walked over to the couch and stood in front of it, staring into the mirror. "If he follows his pattern of associating with the icosahedron, which I'm certain he will." He grinned at his flatmate. "Tonight would be a good night to do it."

"Do what, exactly?"

"Come after me," answered Sherlock, as if it were the most obvious thing in the world.

"I'm sorry, what?" John questioned in shock. "Why would you be a target?"

Sherlock placed his hands under his chin in his classic 'thinking pose.' "John, go stand directly in front of the fireplace." John humphed but did as the detective asked. He turned around to face Sherlock. "Now," the detective stepped to the side, "if you're looking straight ahead, what do you see?"

John looked over at the evidence wall. "All the pictures, papers, and maps you put up."

"But specifically…?"

"Um…the photos of the crime scene and the tattoo."

Sherlock grinned. "Exactly."

John's eyes widened. "What, you mean you're trying to attract the killer?"

Sherlock shrugged. "Yes, so we can restrain him, of course."

John shook his head and ran a hand over his face. "If you want to summon a murdering superhuman that's on you." He snatched up his phone and began heading up the stairs to his room.

-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-

That night was eventful. John had nearly drifted off to sleep several times, only to be awoken by noises from downstairs. By midnight he was a little more than angry at the consulting detective and marched downstairs to give his flatmate a good talking to. When he entered the living room for a moment Sherlock couldn't be found. However, the blogger quickly located the detective in the kitchen.

Before John could even get anything out of his mouth, Sherlock spoke. "John, it shouldn't be much longer."

The doctor folded his arms. "Much longer before what?"

Sherlock looked over at John. "The killer makes himself known." John sighed and rolled his eyes. "Of herself," Sherlock said (mostly to himself), "although the murderer being male is statistically more likely–"

"Sherlock, even you need sleep sometimes," John interrupted.

Sherlock's gaze drifted over to the living room. "John."

"No, Sherlock," the doctor persisted, "you actually need to take into account what your body needs for once."

"John–"

"I don't care if it's 'transport,' it's what keeping you going on your feet, so you'd better get to sleep tonight or so help me–"

Sherlock stood, abruptly cutting off his flatmate's rant. "John!"

The blogger noticed where his friend's line of eyesight was and turned around. There stood a man in their living room, pulling his hand out of the mirror. The towering man glowered down on the two. "What do you know about that symbol?" he questioned, jerking his head towards the evidence board. John's eyes flickered between the photos and the mutant in the room. On the other hand, Sherlock was surprisingly collected.

"Just about nothing," he confessed. John turned to his friend in shock. "I was hoping you would enlighten us."

"You're a copper," the man accused.

Sherlock scoffed and rolled his eyes. "Hardly. And you're the man who killed Evan Warren."

The man seemed to growl. "That monster deserved to die."

"Why?"

"I ain't tellin' you!" The killer lunged for Sherlock who ducked out of the way.

"John, the mirror!" Sherlock called out.

Both John and the killer looked over at the the mirror where the murderer had come from. Catching Sherlock's train of thought, John leapt for the fire pokers, snatched one up, and smashed it into the mirror, causing it to killer yelled out in anger and abandoned his attempt on Sherlock and moved on to John. He pulled a knife from his pocket, ready to strike.

Luckily, he was completely inexperienced and up against a soldier so John easily disarmed the man.

Two against one could hardly be considered fair, but the tenants of 221B overpowered the mutant, rendering him unconscious. Sherlock scoffed. "Amateur," he mumbled under his breath.

-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-/:\-

"So, how'd he know to come and get you?" Lestrade questioned as some other cops ushered the man away in handcuffs.

"Must've caught wind I was on the case," Sherlock said with a shrug. "I'm easier to find than a cop."

Lestrade had his 'I-know-you're-lying-to-me-but-I'm-simply-not-going-to-question-it' face and John understood the facial cue. He cleared his throat. "Thank you though, for coming to help us out," he said.

The inspector sighed. "Not a problem – I would've ended up with him anyway." He thanked the two again and trotted down the stairs. As Lestrade headed down, Anderson came on up. Sherlock's eyes narrowed. "Why are you here?" he sneered.

"You know very well why," Anderson snapped back. He paused the jerked his head down the stairs. "SHIELD will take care of this."

"Of course," John cut in before Sherlock could throw any more insults around. "Keep him away from mirrors. We don't think he can travel through all reflections, but definitely mirrors." He glanced over at the mess of glass on the floor and on the mantel.

Anderson nodded. "Yeah, we'll make sure of that." Without anything more he turned on his heel and left, determined to leave the flat.

John looked over to Sherlock who walked over the window and watched the cop cars drive off. The doctor couldn't exactly think of anything to say, then decided there was nothing to be said and went upstairs into his room.

A/N Phew, got that done! I really struggled with this chapter, so please tell me how I did! Also, if you have any "mutant case" suggestions, let me know in the comments! I have several ideas lined up already, but I will take suggestions that I don't have planned or really like the idea of ^_^