Anyone who knew him wouldn't call Severus Snape a happy person. His Slytherins would call him loyal, hardworking, and dedicated but never happy or even nice. No, those were words used to describe the other professors. His Slytherins knew he would do anything for them, even if it meant putting his life on the line but he wasn't the one they came to when they were homesick or wanted to be coddled.

He did care for his students. He honestly wanted them to all do well in life, even the most annoying ones such as Longbottom. Now that boy was a handful. He would be lucky if he made it through five years of potions without any major catastrophes. Snape found most of the Hogwarts population to be needy, loud, and irritating but he didn't truly hate any of them, at least not until this year.

The one student he would ever hate walked through the entrance doors the night of the opening feast. He had known the boy was coming of course, but hadn't expected to feel such a strong loathing for him. The damn boy looked just like his arrogant, bully of a father. As if that hadn't been enough when he looked up to him during the feast, Snape couldn't breathe for a moment. He had Lily's vibrant, green eyes.

Pain, that's what he felt every time he looked at the boy. He could have possibly gotten over the fact that Potter had his father's face, but to have those eyes changed everything. He couldn't bear to see them again, not after everything that he had done. Every time he looked at Potter, Lily would be looking back at him, judging him.

Of course Potter was one of the only students staying behind this winter break. At least the Weasleys had changed their mind about letting their entire brood stay behind at the castle. He shuddered to think of all the mischief they would get into. But not Potter was alone and Snape thought that might lead to the boy getting into even more trouble than usual.

With most of the staff gone, Snape was in charge. He had taken many courses in healing and was almost as proficient as Pomfrey herself. He was also in close contact with many healers at St. Mungos. He was the most prepared for any situation that arose and being the youngest on staff he was able to do the late night rounds.

He sighed when he glanced down at his watch because it was time to go and make sure all the troublemakers were in their beds. He knew the remaining Slytherins would know better than to break curfew but other students, especially Potter, were not known for following the rules.

He liked to switch up his routine so he started with the kitchens first. He knew that it was a favorite place for the students to go after hours. The elves were much too accommodating.

It was while he was on his way to the portrait of the fruit bowl that he noticed Potter. He grew excited at the prospect of catching the boy unawares. He crept up closer, making sure his feet made absolutely no noise.

He studied the boy, waiting for the right time to make his presence known. He fell back a step when he saw the expression on his face. His eyebrows were slightly arched and the way he scrunched up his features, he looked just as Lily always had when she was upset or confused.

The boy was still wandering aimlessly down the hall when Snape snapped out of whatever trance that expression had put him in. He stalked after the boy calling his name.

"Potter, get back here!"

Potter turned around and looked at him for a moment before his face went slack. He swayed for a second before falling toward the ground like a ragdoll. Snape ran to try and catch the boy but missed as he landed with a hard thump.

He checked the boy's pulse and once he made sure that he was in no immediate danger, Snape conjured a stretcher and brought him down to his quarters. He placed Potter on the couch and ran a diagnostic spell on him. He was underweight, anemic, and suffering from exhaustion. What in the world was he doing out of bed if he was so tired? He had seemed confused; perhaps he was suffering from something more serious.

He put the back of his hand to Potter's forehead to make sure his spell hadn't missed a fever. He didn't feel abnormally hot so Snape was at a loss. He gently shook the boy, trying to wake him but it proved to be a wasted effort.

Snape then turned to the fire. He used the floo powder on his mantle to call one of his oldest friends. Brian Murphy and Snape had gone for their mastery together and while Snape had chosen not to continue on to become a healer, Murphy had.

"Severus?" Brian called, coming next to the fire to talk with Snape. "Is that you?"

"Yes," Snape replied. "I need you to come through. One of my students is ill."

Brian nodded and Snape backed up to let him through.

"What's wrong with him?" he asked.

"I'm not sure. I found him in the halls, looking a little out of it. I called to him and he passed out. He didn't manage to bang his head too hard but I can't wake him."

Brian nodded and walked over to the couch. He waved his wand around in complicated movements, muttering something under his breath.

"How much do you know about him? Is he one of your Slytherins?"

Snape shook his head. "No, he's a Gryffindor, Harry Potter to be exact."

"What do you know of his home life?"

"What are you trying to say? He lives happily with his relatives and is spoiled rotten."

"Are you sure of that?" Brian asked. "Besides being obviously undernourished, I have found some old injuries that could be signs of…"

Snape cut his friend off. "Potter is an arrogant fool, just like his father. No way has he been mistreated, if that is what you are insinuating."

"I need you to keep an open mind about the boy, Severus. I don't want to send him back to a place that's hurting him." Brian tried to explain.

"I'll look into it, alright? Now can you tell me why he has yet to waken?"

Brian shook his head. "It may be because of sheer exhaustion. According to my scans Harry hasn't had a full nights sleep in a long time."

"Probably too busy roaming the castle to catch up on beauty sleep," Snape scoffed.

"Or he could be suffering from nightmares," Brian countered. "Look I don't see anything life threatening and I have a meeting in the morning. Floo me if he doesn't wake by tomorrow afternoon."

Brain went back through the fireplace and Snape was left contemplating the new mystery of the boy-who-lived.

It wasn't quite light out when Snape first heard the screams. He had stayed up far too late watching Potter and making sure his condition didn't change. He considered what Brian had told him. The boy was unnaturally thin but he had an attitude that abused kids just didn't have. He wasn't afraid of authority and had no trouble making friends. Hell, Snape hadn't seen him alone the entire time he was at Hogwarts.

Perhaps he was only seeing what he expected to see. He hadn't deal with a lot of mistreated children; most people in the wizarding world just didn't hurt their kids. It wasn't that long ago, before wizards had invented the right potions, that children died of illnesses all the time. Wizards and witches lived long lives and had long memories. With the past not that far out of reach, children were seen as blessings rather than burdens.

Snape immediately leapt out of bed and grabbed his wand when he heard the first scream. He ran to the living room to find Harry, tangled in the blanket Snape had put over him the night before and clutching his head while shrieking.

"Potter," Snape called to him. "It's just a dream, calm down."

The boy opened his eyes, still holding his head. "Hurts."

Snape summoned a pain potion, tilted Potter's head back, and poured it down his throat.

"Thanks," Potter croaked. "Where am I?"

"You are in my quarters, Mr. Potter," Snape sneered. "And I would like to know why you thought it would be appropriate to be out of your dorm after curfew."

"I-I don't," Potter stuttered. "I don't know. Last thing I remember I was in my common room by the fire."

Snape nodded. "You were suffering from exhaustion and it may have cause you to become delirious."

Potter shook his head and a trail of tears started coming down his face. "No, sir. This just keeps happening. I don't know how to explain it. I just keep losing myself, you know? Like I'm losing time."

"What exactly happens when you 'lose time'?" Snape had a million possibilities going through his mind. Could Potter be possessed? Was this a split personality? Or was it simply exhaustion getting to him?

"I don't know," Potter cried. "I just have all these blank spot in my memory."

"Okay," Snape tried to calm him. "Its alright. We'll figure this out."

He waved his wand to check the boy's vitals. He was fine and it looked like his headache was going away.

"What were you dreaming about?" He asked, changing the subject while he tried to pull his thoughts together.

"The green light," Potter answered. "Its just, well, when I was little I thought it was the car crash but now I know it was when he… you know."

Snape did know. The green light could never be mistaken for anything else in his mind. Potter was remembering his parents' death. He was dreaming of the day that Lily lost her life.

"Do you think you could go back to sleep?" Snape asked. He knew that it was morning but Potter obviously wasn't sleeping well and in the dungeons it was easy to keep everything dark.

"I can try, sir," Potter answered.

Snape nodded and walked to the kitchen. It was small but was equipped with an icebox, stove, and table. He poured mild into a pan and turned the stove on. After waiting a few minutes for the milk to warm up, he transferred it from the pan into a glass. He then walked back to the living room and set the glass on the coffee table beside the couch.

"Here," he said gesturing to the glass. "Drink that, it will help you sleep."

Harry reached for the glass and took a long sip. "Thank you, sir."

"I am going to rest in my room for a bit," Snape told him. "If you need something just knock on my door."

Snape went back to his room and shut the door. He started gathering different books and journals from around his room and bringing them to his desk and began to read.

He had been at it for hours. Searching through every book that might help him but found nothing. Mental illnesses weren't a common thing in the wizarding world and there was little documentation for anything remotely close to what Potter had described.

Possession though, that was another story. There were many books on different ways that possession could occur. Snape knew of Dumbledore's theory on Horcruxes and if the dark lord's soul was trapped in Potter than it could possibly gain enough power to take over for brief periods of time.

That didn't seem very likely though, because if Voldemort was truly taking over Potter's body then he would be doing something much more sinister than just take a midnight stroll around Hogwarts.

He would need to floo Brian and ask his opinion. His friend had mentioned having a meeting so he would get in contact with him this afternoon. It was getting late so he closed his books and went out to go check on Potter.

The boy was fast asleep and didn't stir when Snape went to pick up the empty glass on the table. He went into the kitchen and after he put the glass in the sink, he started to make two sandwiches.

"Professor Snape?" A small voice called from the doorway.

"Come sit," Snape said putting the food on the table.

"Thanks," Potter said, sitting and hesitantly taking one of the sandwiches.

The pair ate in silence and once they had both finished Snape said, "You should go out and get some air. I have some things to take care of but I want you back here in two hours. Is that clear?" At Harry's nod he continued, "We'll need to do some tests to try and figure out what's wrong."

"Okay, bye," the boy said before practically bouncing out of the kitchen.

"Don't forget your heavy cloak," he called after him.

He watched Potter go and cleaned up before heading to the living room to floo Brian.

"Severus?" Brian called out. "Did he not wake up?"

"He did but there is something we need to discuss."

"Alright, I'll step through."

Snape took a step back to allow the other man in.

"What's wrong?" Brian asked.

Severus explained Potter's symptoms and shared his theories on what was wrong with him.

"I'm not sure what it is," Brian told him while he took a seat on the couch. "I'll need to examine him."

"He should be back soon. I'll go get some of the books I had been looking over."

Snape and Brian had been reading over the book and discussing different theories for a while when Potter burst through the door. His cheeks had a pink, healthy glow to them and he looked happier than Snape had seen him since the boy had said good-bye to his friends a couple days earlier. Perhaps sleep had cured him after all.

"This is Healer Murphy, Mr. Potter," Snape said. "He'll be checking you over."

The boy instantly lost his cheer, but it had to be done. Potter needed to get whatever was wrong with him sorted out.

"Hello," Brian greeted him. "Harry is it?"

"Yes, sir," Potter answered.

"No need to call me sir. I go by Brian or Healer Murphy."

"Okay."

"Why don't you come over and sit on the couch. We're going to run some tests and see if we can figure this thing out."

Snape watched as Brian led Potter to sit and started to interview him. It seemed that Potter had been facing this problem, whatever it turned out to be, for a while. The way he answered Brian's questions had Snape on edge. According to what Potter was saying, he hadn't performed any accidental magic from the time he was seven until this past year.

To repress one's magic in such a way, something devastating must have happened. Snape was well aware of what Petunia's views on magic were, and with the rest of the signs it was probable that Brian's suspicions about the boy's home life would prove to be true.

Trying to diagnose Harry took most of the day. Brian took blood samples, conducted long interviews, and tried countless spells but couldn't find anything wrong with him. It was late when he finally collected his things and said goodnight. He promised to process the blood work and check back the next day.

Snape cleared his throat after Brian went through the fire. "You must be hungry."

At Potter's nod Snape led the skinny boy to the kitchen table. He called a house elf and ordered dinner. Food appeared on the table and Snape watched as the gryffindor practically fell asleep in his soup.

"Why don't you go shower and get ready for bed. I'll have a house elf leave pajamas and a toothbrush in the bedroom."

"But can't I go back to my dorm?"

"You could have another episode and you are alone in your dorm. It would be best if you stayed here until we have this all settled."

Potter took one last spoonful of soup and went to go shower. Snape had barely enough time to clean up and go fix up his guestroom before the boy came walking out of the bathroom.

"Here," Snape said pointing him towards his guestroom. "You can stay in my spare room for the night. If you start to feel strange or like your going into one of your trances you are to call to me immediately."

"Okay," Potter answered. "Thank you, Professor."

After Potter closed the door behind him, Snape went to work setting a series of wards. If Potter was agitated or stirred at all, the wards would wake him up. He stared at the closed for when he was done and reflected on everything he had learned about Potter. He seemed more like a hurting child now, rather than a miniature version of James Potter whose only goal was to find trouble.