The tracking charm on Peter Pettigrew would last for another ten days or so—more than enough time for Avada. If he couldn't complete his plan within that span, then it would only mean he'd failed completely…
"With the Marauder's Map in hand, there are just a few final steps left—brew a bit of potion, and then…"
After parting ways with the twins, Avada headed straight for the Room of Requirement on the eighth floor and opened his private chamber. Aside from a few Horcrux-related items that were too important to be left behind and had to stay on his person, most of the miscellaneous research tools and hard-to-carry equipment he needed were stored here.
Compared to the tiny room he'd first carved out—barely larger than a toilet—his private space had now become a spacious, comfortable, fully equipped laboratory. Several tables were neatly lined with rows of bottles and jars, carefully sorted and labeled. Nearby stood a number of large instruments, most of them either self-assembled or hand-crafted by him. And in one corner sat the black Vanishing Cabinet, far tidier than it had been two years ago…
Avada closed the door, pulled open a drawer, and carefully set a wide stone basin on the table. Inside it was a pool of liquid that shimmered with a soft white glow, like flowing light itself.
A Pensieve.
Among wizards—especially those with longer lifespans—this was actually a fairly common item. They weren't hard to find on the market, and prices varied widely. From top-tier models that could perfectly preserve memories for nearly unlimited durations, costing hundreds of Galleons, to cheaper versions that only lasted a few years and sold for a dozen or so. That was what the mental-artifact craftsman recommended by Baron had explained in his letter.
The Pensieve Avada owned was the cheapest model. He only needed it for a few months anyway—and he'd chosen to buy new rather than secondhand purely out of caution, even though he wasn't sure whether something as high-end as a Pensieve even had a secondhand market.
"One last check…"
He carefully lifted a thread of light from the basin with his wand and gently flicked it, letting the end connect to his temple. Closing his eyes, he immersed himself in it for a while before finally relaxing and returning the memory to the basin.
"No problems. Every detail matches. When the time comes, a bit of polishing during use will leave no flaws at all."
Constructing this memory had taken him an entire term and most of a summer. While its total content wasn't especially large, it had to span twelve years in fragmented segments. One misstep, and inconsistencies would be obvious. Even for a master of mental magic like Avada, weaving it flawlessly required absolute focus.
"Next, I'll need some potions… and restraining equipment."
He casually tapped a block of raw wood on the table with his wand. It instantly transformed into a device resembling a mousetrap crossed with a miniature hospital bed. Then, selecting several ingredients from the rows of bottles, he moved to another table covered in glassware and began brewing. Before long, a pale silver potion—faintly luminous—was bubbling vigorously over violet flames.
"Good quality."
Avada nodded in satisfaction, then began calculating again.
"This potion needs about two days to finish brewing. That'll land on the weekend—Ron will probably go to Hogsmeade then, and I can make my move on Pettigrew. If everything goes according to plan, the entire process should take no more than an hour. It'll depend on how long Ron stays in Hogsmeade…"
"Good thing I have the Marauder's Map. I only put a tracking charm on Pettigrew—not on Ron."
He took the neatly folded parchment from his pocket once more, gazing at the dense magical structures etched across it with genuine admiration.
"An absolute work of genius…"
"Even if it relied in part on secret knowledge from the Potter and Black families, it doesn't diminish their talent in the slightest. If those four had devoted even a bit more effort to this direction back then, they would've become top-tier alchemical masters in time."
"Though considering the workload involved… just how much effort did they pour into breaking school rules, exactly???"
In Avada's perception, the map was directly linked to Hogwarts Castle itself. That was why it could so precisely display the true names of everyone inside—except for him.
If he stepped out of the Room of Requirement, his position on the map would appear only as a blot of ink. That likely had the same underlying reason as why the "name curse" couldn't affect its caster—a special interaction tied to the spell's nature.
As for how the map connected to the castle… it was astonishingly ingenious.
Those four had somehow discovered the underlying structural veins of Hogwarts itself, then used an exquisitely clever method to embed a modified Tracking Charm and a True-Name Revelation Charm into the castle's core framework—without disrupting its operation in the slightest. Linked to parchment crafted from special materials, the castle itself became the locator. And thus, the Marauder's Map was born.
Those spells had remained hidden in the castle's main structure to this very day, causing no harm and escaping all detection—despite the fact that Hogwarts' magic was regularly maintained by professors.
The castle's enchantments might indeed be old—something made obvious by the Apparition barrier that only blocked humans—but that did nothing to diminish the brilliance and dedication of the map's creators.
As for why Avada didn't simply make another one himself after understanding its principles—the reason was simple.
The workload was monstrous.
Recreating such a map would require over a dozen potions and alchemical materials just to fabricate the parchment, and seamlessly embedding those spells into the castle's core would take months of painstaking effort. That was the best-case estimate, assuming his ability to perceive magic. The original creators must have spent far longer.
Still, the payoff was equally enormous. Paired with old Potter's Invisibility Cloak, this thing was practically a sacred artifact of rule-breaking.
"…So, for Peter Pettigrew—who witnessed the birth of this map with his own eyes—to fall because of something left behind by the friends he betrayed… isn't that just deliciously ironic?"
Avada shook the parchment lightly, producing a faint crackling sound, then slipped it back into his pocket. After one last glance at the potion still simmering, he turned and left the Room of Requirement without a sound.
(End of Chapter)