Everyone in the Sanctuary was fast asleep. Or so Will Zimmerman thought as he padded quietly down one of the long, empty halls. Halfway down the corridor he froze, his heart thudding wildly as he heard a faint tink, tink, tink.

Was there an intruder in the Sanctuary? Only one way to find out, he thought as he crept towards the apparent source of the noise. The closer he got, the calmer he felt. He seriously doubted that anyone would break into the building at three in the morning just to borrow some lab equipment. Maybe Magnus had just... lost track of time while working on an important project.

"Hey, Mag-" he started to say, poking his head around the door to the lab, but he trailed off, looking confused. "-nus... What are you doing in here?"

The object of his query didn't even bother to glance up from his work, looking quite pleased with himself. Nikola Tesla sat perched on a stool in front of an electron microscope, one hand wielding a scalpel and the other wrapped around a large glass of Chardonnay.

Will grimaced slightly. Tesla always managed to show up at the worst possible times, and he definitely had a bad effect on Magnus. Plus, he had this uncanny ability to make Will feel underdressed, even inside the Sanctuary in the dead of night. Will looked self-consciously down at his faded flannel bottoms and plain white tee. Tesla, as usual, looked dapper as ever, dressed to the nines with a vest and everything. Even a pair of welder's goggles couldn't ruin the picture.

"Still having nightmares?" Nikola asked smugly, ignoring Will's question entirely. "The mother hen said I might notice you prowling the halls at night."

"Magnus told you about that?" Will asked with indignation.

"Not Helen. The big, hairy one. What's-his-name," Nikola said, setting down the scalpel and pushing back the goggles so that they were suspended in his unruly hair.

"What? He-" Will spluttered. "Hasn't anyone here heard of doctor-patient confidentiality?"

"Oh, so Tall, Dark, and Furry has a doctorate, does he?" Nikola threw up his hands in slight exasperation.

"Two, actually. Medicine and astrophysics."

"Of course he does."

"I can't believe the Big Guy told you about that," Will seethed, returning to the problem at hand. "You're not even part of the team. You're just a... a washed-up old has-been, still bent on taking over the world."

"Watch it, pipsqueak," Nikola cautioned, glaring at Will down the blade of his scalpel. "Hasn't anyone ever told you to respect your elders? Besides," he continued smugly, "from what I hear, you haven't been much use to the 'team' lately, yourself."

"Oh, did the Big Guy tell you that, too?"

"No, that one was Helen." Nikola grinned playfully at Will, who just glared back, mouth slightly open.

"Okay, fine," Nikola relented, turning back to a slide he was preparing for viewing under the microscope. "She may have really said something along the lines of being 'worried about you endangering yourself with a lack of focus.'" He smiled cockily at the slide while muttering, "But we both know what she truly meant."

Will ignored his jab, but he still looked rather sullen. "You never said what you were doing in here."

"Neither did you," Nikola retorted smugly. "But, if you must know, I'm looking at a very... interesting blood sample. Care to take a look?"

"What I'm not doing here, Dr. Evil, is playing 'mad scientist' with you. I don't trust you. Not after you tried to kill Magnus."

"That was one time!" Nikola snapped. "When are you people going to let that go?"

Will made a frustrated noise in the back of his throat and his fingers looked as if they were itching to wrap themselves around the other man's throat.

"Just come over here and look at this," Nikola ordered him, standing up from his seat on the stool. "I promise I don't bite. Not anymore, at least."

"You don't scare me, Tesla. Magnus told us you never drank human blood."

"Oh, she's no fun," Nikola pouted, but he quickly bounced back as Will rolled his eyes and approached the microscope. "I can guarantee you've never seen anything like this before," he said, gesturing to the slide.

Will bent down to look into the microscope. He would never admit it to Tesla, but he was rather curious about what had the man so worked up.

"I'm not sure what I'm looking at here," Will admitted as he examined the slide. "It just looks like a bunch of strange blobs. But- wait a minute. Are these... blood cells?" He looked up at Tesla for confirmation.

Nikola nodded with a grin. "Aren't they beautiful?"

"Not exactly the word I'd use," Will muttered under his breath. "They don't look like any blood cells I've ever seen."

"That's because they're not human."

Will looked confused. "But then, what...?" His eyes slowly dawned in realization. He nearly laughed at the scientist's audacity, shaking his head. "The multipedes."

"Give the man a prize," Nikola said smoothly, holding a second slide up to the lab's fluorescent light to examine it. "Now, I know you're not exactly a scientist," he smiled smugly at Will, "but do you notice anything else interesting about the blood?"

Will rolled his eyes but returned his attention to the slide, trying to remember everything he knew from college biology courses. "Well, the cells aren't red, obviously. But they sort of look like red blood cells."

He noticed that the cells were indeed similar to red blood cells in that they had the same approximate shape of normal, healthy erythrocytes, but they were bigger and strangely colored, almost black.

"Right again," Nikola said, and if Will didn't know better he might have thought the man was proud. "Notice how the cells are larger than normal human blood cells? The effects of the source blood increase the osmotic pressure in the body, making the cells hypotonic. And they're so dark because they're not full of ordinary plasma. These cells don't need oxygen; they're already... how do I describe this... supercharged."

"Wow. That sounds, uh, complicated," Will admitted, taking a seat on the stool in front of the microscope. "But why do we care?"

"We care, William," Nikola scowled, "because these little monsters might be more... sinister than we initially thought."

"What do you mean, 'sinister?' I thought we got rid of all of the multipedes. Except for the one you stole from the caverns."

"Ah, I knew you saw that. There may be hope for you yet, Mr. Zimmerman."

Will looked annoyed. "Cut to the chase, Tesla. Are you saying the multipedes are still a threat?"

Tesla shook his head and bent forward to lean on the table, hands splayed. He lowered his voice, almost conspiratorially, and cocked his head toward Will. "Not the multipedes themselves, but their blood."

He straightened up again and began fiddling with some of the items on the table in front of him. Will hadn't taken the time to examine them yet but now that he did, he saw that, along with several blood slides, Tesla had out an array of medical instruments.

While Will watched, Tesla delicately grasped a vial of blood with his long, slender fingers. This blood was red, definitely not from the multipedes. Without taking his eyes off of the blood, Tesla picked up a syringe from table and drew some blood from the vial. He stared at the syringe almost hungrily, eyes wide and bright.

"Remember how the multipedes were drawn towards our blood, mine and Helen's?" He still wasn't looking, but Will nodded regardless. He felt that Tesla had probably forgotten he was in the room, anyway. His eyes had a distant quality, as if he were looking at something- or someone- very far away.

"I initially thought that they were attracted to the source blood because they sensed a familiarity, a kind of instinctual call toward kin," Nikola continued. "But I was wrong."

He took out a blank slide and let the needle of the syringe hover over it. Gently, he eased the plunger down, letting a small droplet of blood fall onto the tiny glass plate. He grabbed another syringe, already full of the multipede's murky blood, and dripped some onto the slide, letting the two mix together on the glass.

Will looked confused and opened his mouth to speak, but Tesla quickly silenced him. "Just wait," he said, nodding almost imperceptibly. He placed another clear glass plate on top of the first and carefully slipped it into the microscope.

"Watch."

Stepping up the microscope, Will looked on, astonished, as the magnified blood started to shift. At first the motion was barely visible but gradually the cells increased their pace, beginning to churn.

Puzzled, Will raised his eyes from the microscope and glanced over at Tesla who merely shook his head once. "Keep watching."

Will returned his attention to the blood and was astonished to note that the ordinary red cells appeared to be shriveling and dying. As he watched, the red cells visibly deteriorated. Within thirty seconds they were completely destroyed.

Will whipped around to face Tesla, amazed. "The multipedes weren't attracted to your blood," he said, brow furrowed. "They were trying to destroy it!"

"Mm, sort of," Tesla said, narrowing his eyes and shrugging a shoulder, prevaricating. "It's not as simple as that, though I don't expect you to understand."

"Seriously?" Will said, annoyed. "Psychology is a science, you know!"

Nikola just raised an eyebrow at him, smiling a smug little half-grin. Before that jab he had gone nearly five minutes without mocking the boy, a personal record for him.

"Okay, so, remind me why this is important to me?" Will asked.

"It's not, necessarily," Tesla said calmly, examining his fingernails. "At least, it doesn't directly affect you. You have normal hemoglobin, after all."

"So this is all about you? You're in danger so you brought me over here to show me your blood?"

"I didn't ask you to come in here," Tesla snapped at him, throwing up his hands. "You did that of your own accord. Besides," he said defiantly, his bright eyes boring into Will's own. "The blood isn't mine… It's Helen's."