Just as Severus flooed his final grade reports to the Headmaster's office at precisely 11:59 PM, a low whimpering traveled down the hallway from Harry's room. The Potions Master forwent his celebratory glass of fine red wine that had been sitting under a cooling charm waiting for him as motivation for the last hour and strode down to Harry's room.

"Sirius," Harry moaned in his sleep as Severus swept into the room. The Slytherin groaned with the mention of the mangy mutt. He'd grown past hating Black for their childhood fights to hating him for the man's impulsiveness. If he hadn't ran off to the Ministry, he'd be here for Harry like he was supposed to be, not dead causing the child nightmares.

The child had thrown off his covers except for one sheet, which was tangled up around him. Perspiration beaded his forehead as he thrashed around trapped in a nightmare.

"Harry," Severus called from across the room as he approached the bed, not sure if he should touch the boy to wake him or if it would do more harm than good.

"I deserved it!" Harry screamed. "Sirius, I killed you!"

"Harry," Severus tried again, lightly shaking the teen. It was imperative to get Harry out of the nightmare to address that last statement. A sense of urgency set in as Harry threw his arm off and screamed so loud it made his ears ring.

Not knowing what else to do, Severus climbed into Harry's bed and took the boy in his arms, restraining him from moving by holding him against his chest, his arms pinned to his side. Harry struggled to break free, but the Potions Master had the advantage through both size and strength. The screams continued and Severus thanked Merlin ten times over for being paranoid enough to have his quarters warded with silencing charms lest Harry wake up the entire dungeons. The Potions Master refused to let go of the boy and waited for him to exhaust himself. Finally, after a few of the longest minutes Severus had ever experienced, Harry's screams dampened to whimpers and his body relaxed.

"Wake up, Harry," Severus whispered into the boy's ear. Blinking, the boy surfaced from sleep wiggling under his tight grasp. He loosened his arms as he waited for Harry to fully wake.

"Sir?" the teen asked, his voice hoarse, no doubt from the constant screaming. Merlin, the child gave him a headache. Were his nightmares always that bad, or did Harry save up an extra nasty one just for him?

"Drink," Severus ordered after conjuring a glass of water and handing it to Harry.

"Thank you," Harry said handing the glass back to him after a few drinks. Severus set the glass on the nightstand. "What happened?"

"You don't remember?" Severus asked, raising an eyebrow.

"I had a nightmare, didn't I?" the teen assumed putting the pieces together.

Severus nodded, surprised. He had no idea how someone could forget a nightmare like that, he certainly never did. "We need to discuss what you said in your dream."

"Do we have to?" Harry shivered, burying his head in Severus' robes to avoid the Potions Master's gaze.

"Yes," he insisted summoning the fallen comforter from the floor with a wave of his hand and spreading it over Harry. "Do you blame yourself for Sirius' death?" Severus asked being careful not to have any negative inflection in his voice at his childhood rival's name.

"No," Harry said too quickly for Severus to believe from the folds of his robes.

"Are you sure?" Severus pressed.

"Maybe," Harry whispered. "It was my fault."

"Harry, sit up" Severus began, his voice dead serious, nudging the boy to follow his orders. The teen reluctantly sat up, his eyes glassy and holding unshed tears. "Did you raise your wand to your godfather?"

"No," Harry shook his head.

"Did you force Sirius to follow after you to the Ministry or push him into the Veil?" the Potions Master asked knowing the answer, as he was present at the Ministry, having gone after the boy when the Order didn't respond fast enough which led to his cover being blown.

"No."

"Then how is it your fault?" Severus tried to reason with the teen.

"Because I went there," Harry insisted, crawling out of Severus' arms and leaning against the headboard, his knees pulled up to his chest. Flurry settled herself at his feet. "If only I'd have taken your lessons seriously, I wouldn't have let Voldemort lure me there."

"Even if I was successful in teaching you Occlumency, there was a chance the Dark Lord would've broken through your shields anyway," Severus told the teen. "Have you thought perhaps that Sirius was an adult who controlled his own actions? He was waiting for a reason to leave Grimmauld Place, and as an adult it was his choice to go to the Ministry, no one else's."

"But...but he was responsible for me! He couldn't have just let me go off there alone!" Harry argued, hugging Flurry close to his chest.

"Harry," Severus pleaded, trying to get through to the boy. "You weren't alone. I was there as well as the rest of the Order. Sirius knew that. His death was in no way your fault."

"Are you sure?" Harry asked, his voice small and trembling, afraid of the answer.

"Positive," Severus reassured the child, reaching over to squeeze his knee.

"SoIdon'thavecancerbecauseIgotSiriuskilled," Harry whispered, too low and squished together for Severus to understand.

"Pardon?"

"My leukemia isn't from getting Sirius killed?" Harry said a little louder and slower for Severus to hear.

The Potions Master's heart stopped. Did the child really believe he deserved cancer, and that he did something to get it?

"Harry, listen to me," Severus whispered, pain in his voice. "You did nothing to deserve leukemia."

"Really?" Harry asked, his face lighting up with hope.

"Really. Do you remember what Madame Pomfrey said about what cancer is?" Severus asked. It was important Harry understood he could've done nothing to prevent or catch cancer.

"I didn't really understand it," Harry admitted with a shrug.

"Cancer happens when something triggers your DNA, that's the things in your body that make you, you, to start sending bad cells to divide at a rapid pace, and those bad cells are the cancer cells that go on to attack your body. Everyone has a few cancer cells in their body when they're born. It's when your DNA is triggered that it progresses into what we call cancer," Severus tried hoping it wasn't above the boy's level of knowledge.

"So you have cancer cells, too? Just not a lot like I do?" Harry asked.

"Yes, or as you alluded to in the Hospital Wing, everyone has a Dark Lord, it's when that Dark Lord decides to recruit Death Eaters is when there's a problem," Severus explained.

"But how does our Voldemorts decide to begin recruiting Death Eaters?" Harry wondered. Severus cringed at Harry's liberal use of the Dark Lord's name, too many years of spying and training himself to refer to the evil megalomaniac as the Dark Lord left its traces. 

"That is the question that doctors have searched for the answer to for decades. No one knows," the Potions Master said with a shrug.

"Oh."

"Flurry seems to like you," Severus changed the subject. With any hope, he could get the boy back to sleep soon, giving them both time for much-needed rest.

"It's strange, usually animals don't like me," Harry admitted, looking down at the furry little ball of fluff, "except Hedwig and a few of Hagrid's creatures."

"It doesn't surprise me that Flurry likes you," Severus said, reaching over to scratch his cat behind her ears. Perhaps he could manage to tell the teen one tidbit of information to send his thoughts away from his nightmare and godfather. "Would you be surprised if I told you she's older than you are?"

"How? She's a kitten?" Harry looked up at him, searching his face for a lie.

"She's not a normal house cat, but a different breed that the wizarding world calls Feles Felices or lucky cats. They are usually the familiars of a Potions Master or aspiring Potions student for their luck, and because they have an uncanny ability to know when a potion is going to explode or boil over and to seek shelter," Severus looked at his cat wistfully.

"But how can she look like a kitten? Is that part of the breed?" the teen asked, confused. Apparently, Hagrid hadn't gotten around to teaching his students about Feles Felices. Then again, they were small and harmless, both of which characterized creatures Hagrid wasn't interested in.

"Yes, they also have a life expectancy of around fifty years, so she's still young." Severus informed Harry.

"So she's your familiar from school?" the teen pieced together.

"No, she was your mother's," Severus admitted with a sad smile. "Flurry probably remembers your scent from when you were a baby."

"My mother's?" Harry asked, surprised, as he hugged her closer. Severus didn't have to read the child's mind that he savored the link that cat held between him and his mother. "I thought my house was destroyed?"

"It was, but Flurry is a smart cat. She was found guarding you in your crib, and Professor Dumbledore gave her to me knowing that Flurry liked me. At the time, I intended to give her to you when you started Hogwarts, but she grew on me," the Potions Master admitted sadly. Even when the little monster ripped up his homework as a teething kitten, she somehow managed to make him forgive her. 

"But how-"

"Despite the memory you saw in the Pensieve, Lily and I managed to reconcile. Flurry was a present from your grandparents for Christmas fourth year." The same year Jesse died from leukemia, Severus remembered, blinking. "She wanted to call the kitten Snowball, but I insisted that the name was too nausea inducing and suggested Flurry instead."

"Will you tell me more about her, my mother I mean?" Harry asked, his emerald eyes shining.

"Not tonight," Severus stated. He couldn't handle any more. Telling the child about Flurry was hard enough. It was painful talking about Lily to the child that signified how much he lost. James Potter got everything; fame, a reputable career, a child, and most importantly the girl. All Severus got was her cat.

"Why?" Harry yawned.

"Because it's late, and you need to sleep," Severus reminded the teen getting up off the bed to smooth down the sheets and spread out the comforter. "Lay down."

Harry slipped under the covers, Flurry tucked in his right arm. "Good night, sir."

"Good night, Harry." Dimming the lights and clapping on Harry's wall mural, Severus turned to leave to seek the privacy of his room, knowing his revelation about Flurry all but guaranteed pleasant dreams for Harry.

"Professor?" the teen called as he reached the threshold of Harry's door.

"Yes?" Severus turned to look back at his charge.

"Thank you, sir" Harry flashed him a tired smile.

"Severus," the Potions Master corrected, tired of Lily's son calling him professor or sir numerous times a day.

"What?" Harry asked, surprised.

"You may call me Severus," the Potions Master offered. "Lily would want that."

"Severus," the child tested out.

"Yes, that's how it's said. Now to sleep with you, brat," Severus chided before their chat could grow any sappier.

"I'm not a brat," Harry insisted.

"You're the brat who stole my cat," Severus declared. "Good night."

"Good night, Severus," Harry responded. The Potions Master rolled his eyes, vanquishing the lights as he left the boy's room to the sounds of the cheeky brat's protest, wondering if he made a mistake letting the boy call him Severus.

------

After a blissful night filled with dreams of a redheaded girl with a white fluffy kitten, Harry protested when Snape...Severus shook him awake. "Did you sleep well?" the man asked already dressed for the day, dark circles evident under his eyes.

"Yeah," Harry smiled remembering the girl, his mother, chasing Flurry around a peaceful meadow next to a stream, laughing as the kitten hopped through the long grass.

"Good. I must see off the Slytherins soon, but there are a few things you should know before I go," Snape said, perching on the edge of his bed.

"Okay," Harry reached for his glasses and slid them onto his face.

"After I return, we're due to meet the specialist," Severus reminded him.

Harry frowned. He didn't feel like being a human pincushion today or any day.

"We can't put it off any longer," Severus sighed, squeezing his shoulder.

"I know," Harry trailed off wishing to be back in the meadow with his mother and Flurry.

"She's going to examine you before installing your Hickman," Severus rubbed his shoulder as he tensed. Harry didn't want to feel pain again; the bone marrow biopsy was enough. "Harry, we discussed this."

"I'm scared," he admitted. "I know it's going to hurt."

"It won't be like the bone marrow biopsy," Snape promised. "You'll get an IV in your arm, so we can give you some drugs that'll make you forget the whole procedure and likely make you sleepy. It's a technique called conscious sedation."

Harry liked the sound of forgetting the whole thing. "I won't remember?"

"No, the procedure should take about an hour, and the drugs will wear off soon after. You'll be sore and may be in a little pain, but there will be painkillers ready for you to take. Most likely you'll sleep through most of the day," Severus reassured him.

"Will I have to stay in the Hospital Wing?" Harry hated that place. He wanted to return to his bedroom with his mural, large bed, Flurry, and even Snape.

"Once your vital signs return to normal which shouldn't be long after the sedation drugs wear off, the specialist will clear you to return here, and for the rest of the day and tomorrow, you won't have anything to do but rest and relax."

"Okay," Harry sighed. "You'll be there, right?"

"Yes, if you wish I can start your IV instead of the specialist," Severus offered.

"I'd like that." Knowing the Potions Master would be gentle helped his anxiety over the IV a lot. Severus wouldn't harm him any more than necessary.

He watched Snape pull out a stack of forms from his robes' pocket. "These are the consent forms for your treatments and procedure. Is this your wish still?"

Not really having to think about it, Harry nodded. His options were to undergo treatment or die, and he didn't want to die. Snape, Severus promised he wouldn't let him.

"I'll just sign these then." The Potions Master made a show of taking out a never-out quill and signing each form, one-by-one. Snape didn't have to do that, but Harry appreciated the gesture. It meant Severus was keeping his promise of listening to Harry and considering his opinions. "All signed. As part of your procedure, you can't eat or drink anything, so while I'm gone take a shower, dress in a pair of pajama bottoms and your robe, and relax until I return."

Relax? Did Snape honestly think he'd be able to relax? He wasn't the one waiting to be cut into so they could stick a tube in him and leave it there!

"Harry," Snape soothed, running the back of his long fingers across his cheek, "it'll be okay."

Grabbing Snape's forearm, Harry wrapped his arms around it, pulling it to his chest, needing the physical contact to remind him this wasn't a nightmare. "Don't go," he begged.

"I have to," Severus said, torn. "It should take less than an hour. The students are already making their way down to the train."

"Okay," Harry whispered defeated as he released Snape's arm. "I'll just take a shower and play with Flurry."

Severus stood up, but not before squeezing Harry's shoulder one last time. "Flurry doesn't mind water," he added. "She'll jump in if you let her."

Harry nodded and watched his professor leave until he couldn't see him anymore and heard the door click close. Gulping, Harry pushed himself out of bed and gathered clothes from his wardrobe before heading into his bathroom, Flurry in tow.

After a quick shower, Harry got ready, but neither task took much time, even with the extra step of drying Flurry, leaving Harry with nothing to do but wait. He wandered out into the sitting room and sat on the sofa, staring at the door, waiting for Snape to return.

"Meow," Flurry rubbed up against his leg, a plastic stick in her mouth with a toy mouse attached by a string dragging behind her. Harry reached down and took the stick from the cat, waving it around for her to attack.

Severus returned after Flurry managed to pull the stick away from him for the fourth time. "Ready?"

Harry nodded, not trusting his voice.

"Come then. She's waiting for us," Snape directed, his tone sounding ominous to Harry. Dropping the cat's stick, he walked over to Severus who put his hand around his shoulder and squeezed. They walked to the other side of the sitting room to the door that now led to a small entrance chamber that housed the floo, a sink, and a small wardrobe. The Potions Master took a pinch of floo powder before guiding Harry into the floo and calling out their destination. There was no turning back now.