Not all of Harry's letters were a source of joy for me. Early on, it was made clear one Professor Snape had sank below the standards of behavior. As a professional who often dealt with children, I was appalled, and prepared a letter for the headmaster forthwith. I was fully intent on sending my scathing missive when the mail owl next arrived.

Holmes, to my surprise, objected.

"If I," said he, "Acted against every man and woman who bore me hatred, I should never rest. I've found such ones best left alone. Hostility ignored may smolder in dormancy, but attention often stirs emotion to fullness."

In the end, it was not delivered, but I still have the letter.

-Excerpt from A Study in Magic, by John Watson, MD

-oOo-

Hogwarts on the weekend was a different beast. Gone were the hoards rushing from class to class. Students and teachers alike unwound from the long week, recharging before the inevitable return to academia. Younger kids played around the lake, skipping rocks and hoping for a glance of Hogwarts' giant squid. On the pitch, impromptu games of snitchless quidditch wiled away hours for older students. Activities varied as wildly as the students themselves.

Why, a few were even getting ready for a synchronized assault.

-oOo-

Harry Potter marched towards the Defense classroom and mentally reviewed the plan of action. It was a simple plan, but he been taught the merits of simplicity long ago. As he laid his hand upon the classroom door, some of Sherlock's words came to mind, like a cork bobbing from the depths of memory.

"With excess power or ability, it becomes easy to seek the most complex solution, even when the simple solution suits best."

Harry opened the door, entered the classroom-turned-kitchen, and noted he was last to arrive. He acknowledged murmured greetings with a curt nod. The first-years sat once again at a table laid with tea. Harry joined them, and observed none of the cups had been touched. After Quirrell's last introduction, paranoia seemed to have taken a swift grip on the student's minds.

Harry clasped his hands together and looked around the table. The first-years looked back with faces tinged by an underlying excitement.

"Ready?" asked Harry.

Everyone nodded. They'd all gone over the plan, carefully memorized their roles, and were to redeem their previous, paltry attempt.

Harry stood. "Then let's move out."

They walked to the green door as one, orderly and single-file. Harry grasped the doorknob. "On three," he said, "One..."

Luna tapped her necklace, nails beating a mini drumroll.

"Two."

Neville reminded himself to breathe. His heart felt like a Golden Snitch trying to escape his chest.

"Three!"

Harry threw open the door and careened down the corridor. Behind him, footsteps pounded. At the intersection, Susan screeched to a stop, Hermione ran down the left hallway, and Hannah swerved down the right. Harry and Neville ran straight on through the northern corridor. As the pair drew close to the halfway point, Harry slowed to a jog before stopping, and watched his partner continue to sprint full speed into the gloom.

-oOo-

Neville panted like a dog. His arms burned, his legs burned, his lungs burned, even the sweat dripping into his eyes burned.

But he kept running.

Over and over, Harry had said the plan relied on speed. The faster they moved, the better their chances. They weren't outfighting the professor, he reminded them, they were outmaneuvering him. Neville gulped another breath of stale air and continued to ignore the fire in his limbs. Even at the hallways end, faced with a closed door, he slowed only slightly. Never stopping, he reaching out mid-step, violently twisted the doorknob, and slammed the entrance open with enough force to knock dust from the doorframe.

He didn't even spare time to examine the familiar, untidy room. He bolted to the far wall, scooped the glowing sphere off the shelf, thrust it into his pocket, spun on his heel...

And froze.

The doorway was blocked by a man draped in tattered robes. His face was hidden by a dark mask, and from behind that mask came a voice, scratchy and distorted. It was Quirrell.

"You're early."

Neville swallowed and took a single step backwards. "Why is it always me?" he thought. Flashes of his last encounter with the Defense Professor came and went. Quirrell outclassed them all in every way.

During their planning, Harry had offered one piece of advice, before all others. Neville remembered it clearly. "If you meet Quirrell, try to make it last. Do the unexpected, and try to buy the rest of the team as much time as possible."

Neville's eyes darted around the cluttered room and settled on a rickety footstool. Still gasping for air, and heart somehow beating faster than ever, Neville lunged for the stool and raised it above his head.

Quirrell gave his wand a lazy wave, and the stool turned to sawdust.

"Unusual tactic," said the professor, "But too slow."

Neville lowered his arms and looked at his hands in shock. Grasped in each were the small remainders of his improvised weapon. He gamely chucked the furniture remains at Quirrell's head, but was suited more as a gardener than gladiator. One piece hit the wall. The other impacted the ceiling.

Quirrell shook his head, sighed, and extended his wand. "Accio wand." Even as the spell snatched the wand from Neville's grasp, Quirrell was moving.

Later, Neville would find it impossible to pinpoint the exact moment of contact. One moment Quirrell was lunging across the room, and the next moment he was on his back with the Defense Professor standing over him.

"Disappointing," said Quirrell. "Surely, your parents must have raised you better than this?"

Neville clenched a fist and threw it at professor's face. Quirrell laughed and swayed backwards, just out of range.

Then Neville opened his hand, and slung sawdust into Quirrell's eyes.

The professor snapped up, shook his head, and ceased laughing. "Better," he shook hi shead again, "Improvise with what's at hand."

Neville was still flat on his back, but he kicked out anyway, aiming between the professor's legs.

Quirrell moved like a viper, and caught his ankle in an iron grip. "That's enough," he said, and leveled his wand at Neville. "A decided improvement, Mr. Longbottom. Goodnight."

-oOo-

Too long, thought Harry.

How many minutes had it been now? Neville should have been back before now. Only one thing, or one person, could be keeping him occupied. If that was the case, it was time to go.

Harry turned and jogged back towards the intersection. Soon he made out the telltale glow of Susan's wand, and approached her.

"Is everyone out?" he asked.

Susan nodded. "You just missed Hermione and Hannah. We're waiting on you guys." She looked over Harry's shoulder. "Trouble?"

"Probably," Harry gave the northern corridor a long look before finally shaking his head. "We should go."

"But, what about Neville?"

Harry was already moving back towards the kitchen. "He's not making it."

-oOo-

Zacharias grinned like a Cheshire cat. "So let me get this straight. You just left him?"

The first-years crowded around Harry and peppered the boy with questions. Only Luna stayed at the table, as she languidly spun two glowing spheres.

Hermione frowned. "You didn't even check on him?"

Harry shook his head and poured a cold cup of tea from the table set. "He was late, and it was time to pull out."

The first-years speculated and guessed at Neville's fate. Zacharias in particular seemed to enjoy considering the many ways Quirrell could truss Neville up. Harry ignored them, waved his wand over his teacup, and took a small sip.

Hermione saw him drink and surged forward, laying a hand on his arm. "Don't drink it! Don't you remember what Quirrell said?"

Everyone quieted and waited to see if the Boy Who Lived keeled over. Harry continued to sip.

Hermione narrowed her eyes. "Explain."

Another sip. "Explain what?"

"Explain."

Harry shrugged. "It's just a filter spell."

"For poison?"

"For water."

Susan scratched her head. "Still needing an explanation here."

Harry set his cup down. "The spell is designed for making clean drinking water. It removes anything classified as an impurity." He frowned at his cup. "Unfortunately, it appears tea is categorized as such." Harry tilted his cup, revealing not tea, but clear water.

"What happens if you cast it on a person?"

Five sets of eyes turned to stare. The attention didn't faze Luna Lovegood in the slightest.

Harry swallowed, did his best to forget humans were eighty percent water, and carefully concealed his unease. Hermione's response was more externalized. She looked horrified.

"I'll ask a professor," said Harry.

"Ask me what?"

Professor Quirrell stepped through the green door, levitating Neville behind him. The professor placed the unconscious student in a seat, posed the boy as one would a doll, then seated himself.

"Ask me what?" Quirrell repeated.

Harry glanced at Luna. "We were wondering what happens if you cast aquius purificus on a person."

The professor shrugged. "The purifying spell? Nothing. Purificus requires line-of-sight to cast. You have to be looking at water, or something very close to water."

Harry let out a very quiet, very relieved breath.

"Now, said Quirrell, "If we've had enough fun contemplating spell lethality, it's time to move on," he pointed his wand at the comatose Neville, "Enervate."

Neville's eyes shot open, and he almost fell sideways out his chair. He caught himself and looked around the table with a small grin. "Did we win?"

Quirrell tapped the table, drawing everyone's attention. "That depends. If you don't forget the lesson, then yes, you win."

Wide smiles split the student's faces, and Quirrell continued. "You outmaneuvered a superior opponent with speed and numbers. Congratulations on a well-executed plan." Quirrell nodded solemnly and ignored Susan's attempts to high-five everyone. "You'll be happy, I'm sure, to know the next test will be in a new environment."

Harry's suspicions were confirmed. The house had been designed from the ground up, after all, to teach a specific lesson.

Quirrell gave a casual, two-fingered salute. "Dismissed."

The group of first-years leaked from the classroom, talking amongst themselves about next weeks "new environment". Harry remained seated. When Neville shot him a questioning look, he nodded towards the professor.

"I'll catch up later."

Neville shrugged and continued on his way. As the door shut, Quirrell leaned back in his seat.

"Question, Mr. Potter?"

Harry nodded, and turned his inquiry around in his head.

"While we're young, then."

"Sorry," said Harry, "I'm not sure if you'll like the question."

Quirrell raised an eyebrow. "Just ask, and if I don't answer, don't ask again."

"Fair enough. So...why are you doing this?"

"Doing what?"

Harry gestured broadly, taking the kitchen. "All of it. The defense club. You don't seem the type for it, and it makes me curious, is all."

"Oh? And what type do I seem?"

Harry shrugged. "Same as my dad. Loner. So the question is: Why?"

Quirrell's gray eyes bore into Harry's green. For a while, student and teacher just sat and stared..

Finally, Quirrell answered. "In the last one hundred years, dark wizards or witches of notable power have surfaced with increasing frequency. In the past two generations, in Europe alone, we've had two consecutive Dark Lords."

Quirrell paused, and Harry noted the lack of focus in the professor's eyes. "The Ministry," said Quirrell, "Was an absolute mess during Voldemort's rise. It assured the public everything was under control, when nothing could be further from the truth. That kind of cover-up helped the Dark Lord consolidate his power base faster than anything else. After the war, it became popular to blame the Minister, blame Voldemort, even blame dark magic itself."

"I never," said Quirrell, "Heard anyone blame ignorant, incompetent men. Even if they condemned families just as surely as a Killing Curse." Professor Quirrell shook his head and refocused on Harry. "One day, Mr. Potter, you're going to see the world go dark. When that happens, let no one say you are unprepared, ignorant, and incompetent. Let them say of you what none said of me: that you are ready."

In the ensuing silence, Harry realized he hadn't seen Sherlock Holmes in a very long time.