The brief encounter with Harry and Ron did nothing to dampen Sherlock's mood for a walk.
Every year, as Christmas approaches, the temperature drops low enough for the Black Lake to freeze over with a thick layer of ice.
Seen from high up in the castle, it looks as though a mirror has been set into the snow.
When Sherlock reached the lakeside, he felt an urge to skate across it.
But a handful of students were still loitering nearby; to keep up appearances, he forced the impulse down.
As he strolled past the Whomping Willow that Harry and Ron had wrecked at the start of term, he suddenly heard raised voices ahead.
"What are you doing here, Weasley?" a sneering, mocking voice rang out.
It was Draco Malfoy, flanked by his ever-present shadows, Goyle and Crabbe.
And the one he was taunting was the third Weasley son—Percy Weasley.
Percy bristled at Draco's words.
"You will show a prefect some respect!" he snapped. "I don't like your attitude!"
Draco smirked.
"You're a Gryffindor prefect—don't throw that title at me."
His voice dropped, thick with glee.
"You've heard, haven't you? Your father was fined fifty Galleons because of that idiot brother of yours—that must be your entire savings. Pathetic. So what did Mummy send you for Christmas? A cold sandwich? Ha!"
Goyle and Crabbe guffawed in chorus.
Seeing Percy's face twist with rage made Draco's day.
Ever since Sherlock had sentenced him to scrub the first-floor toilets until New Year's, life had been miserable.
Even pleading with Snape had failed; the Potions master merely said the punishment was deserved, leaving Draco even more wretched.
Then, a few days ago, thanks to his father's maneuverings at the Ministry, Mr. Weasley had been fined for Harry and Ron's flying-car stunt.
Though not the dismissal the Malfoys wanted, the fifty-Galleon fine—about three months' wages—still stung.
Running into Percy today, Draco couldn't resist rubbing it in to vent his own spleen.
"Pity the Ministry didn't sack your father—then your whole brood would starve!"
Draco poured every ounce of resentment into venomous words, cursing Percy.
"The Heir of Slytherin ought to clean house—purge not just the mudbloods but pure-blood failures like you. You and your four idiot siblings deserve to die!"
Percy's face burned crimson; even his rule-bound patience snapped. He whipped out his wand and aimed it at Draco.
"Stupefy!"
A red jet burst from his wand, streaking faster than the eye could follow toward Draco.
Caught off-guard, Draco stared in terror, too late to dodge.
At the last second, Crabbe yanked him sideways, and the curse whistled past his ear.
The Stunning Spell clipped the castle wall, shattering a windowpane.
A sharp tinkle of glass echoed across the grounds.
"You dared cast at me!"
Draco's shriek cracked with disbelief.
Everyone knew Percy was the most rule-abiding Weasley; that was why Draco had felt safe to taunt him.
But whether the insults had gone too far or Percy was simply in a foul mood, he had broken school rules and struck first.
An instant later, Draco, Goyle, and Crabbe whipped out their wands, faces contorted.
Though Percy was three years above them, three wands against one made the odds easy.
Just as Percy was about to be overwhelmed, a cold voice cut in.
"What do you think you're doing?"
The trio froze, wands half-raised, and glared at Sherlock as he strolled up, expressionless.
"Professor! Weasley attacked us first—dock points! Make him scrub the toilets!"
"Are you telling me how to do my job?"
Sherlock's voice was as chill as the lake ice, cold enough to kill.
Draco quailed under that gaze and bit his tongue.
Sherlock had watched the entire scene; he hadn't intervened when Percy cast, hoping the prefect would teach Draco a lesson.
When the spell missed, he stepped in to spare Percy worse trouble.
By the rules, Percy had struck first; punishing Draco would mean punishing him as well.
So Sherlock merely said icily,
"What are you all still standing here for? Shall I take points from both Gryffindor and Slytherin?"
Draco shot Sherlock a venomous look, then stalked off toward the castle with his cronies.
Percy trudged back, head down. As he passed Sherlock, he murmured,
"Thank you, Professor Cavendish."
Sherlock gave a slight nod and said nothing more.
Watching them leave, he shook his head in resignation.
In a fully enclosed boarding school like Hogwarts, student spats—and even outright bullying—were daily fare.
Yet with barely half a year at the castle, Sherlock could only intercede now and then to help the underdog.
He squinted up at the window Percy's curse had struck—one on the eighth floor.
From the angle, it looked like… the Headmaster's office!
Setting down his quill, the aged Albus Dumbledore stretched stiff limbs.
He frowned at the parchment he'd been pondering all morning, then plucked a Bertie Bott's Every-Flavour Bean from the box.
"Ugh!"
Two chews, and he spat it out in disgust.
Seven beans in a row had tasted of pepper or earwax; hardly a normal flavour among them.
His luck had soured ever since unwrapping his Christmas gifts that morning.
First, he'd tripped on the stairs; back in his office, a mountain of memos from the International Confederation of Wizards awaited.
Christmas Day, and still the world dumped its troubles on him!
The sweets were bad enough—then a real cockroach had crawled out of the Cockroach Cluster Sherlock had given him, nearly ending up eaten.
As the beleaguered headmaster rose to pace,
"Bang!"
A scarlet spell shattered his office window.
Dumbledore stood like a statue, icy wind whipping through the gap to slap his lined face—fortune mocking him.
Grim-faced, he drew the Elder Wand and began a careful self-examination.
Something was very wrong; perhaps someone had cursed him.