Among all the conditions for growing a golden apple tree, only one actually mattered: energy. The tree wasn't particular about the source. Dark magic, ambient magical discharge, the residual warmth of living creatures, it consumed all of it with equal enthusiasm and no complaints. In terms of raw cultivation difficulty, the thing was practically self-sufficient.
The single requirement was volume.
Without a sufficiently dense and continuous energy supply, the tree would simply sit there, absorbing whatever trickled past, and flowering would take decades. Planting it somewhere like Hogwarts and letting it graze on ambient magic, the way the Whomping Willow did, was an option in the same way that waiting forty years was an option.
Tom's initial plan had been to manufacture nutrient solution by extracting energy from living creatures and applying it directly to the roots. Expensive, but he had money. Still, there was something about paying heavily for something that could theoretically be obtained for free that grated on him.
High-density energy sources. He ran through the candidates in his head. The Philosopher's Stone came to mind first, naturally, but its value made it impractical to use as fertilizer. Then the lake.
Voldemort's Horcrux lake. Two thousand Inferi soaking in it for decades, fed by a magical array designed to concentrate and convert dark energy. By any reasonable estimate, it was one of the highest concentrations of dark power anywhere in the world.
And the best part: it didn't belong to anyone who could object.
We're both Tom Riddle. You've had your decades with it. Now it's my turn.
Tom laid out the apple tree's requirements and his idea. All four of them went quiet for a moment.
The man was mining Voldemort for resources.
It was, however, hard to argue with.
"You're planning to excavate a lake into the small world?" Ravenclaw asked. Tom nodded. She continued: "Reasonable approach, but the dark energy dispersal becomes a problem the moment it's outside the original containment. In the cave, Voldemort's own enchantments kept everything channeled toward the lake. Your small world doesn't have that infrastructure."
The problem was real. Tom frowned and thought for a moment.
"What if I bring the cliff face in with it?"
"Your Shrinking Charm reaches that scale?" Grindelwald looked genuinely startled.
Compressing an entire cliff formation down to something transportable wasn't a thought he'd entertained as even theoretically possible.
"I could disassemble it first and reconstruct it on the other end," Tom said, working it out as he spoke. "It's just building a mountain. Tedious, but not actually difficult."
"I'd suggest a dedicated growing enclosure instead."
Ravenclaw offered her own version. "The lake's energy isn't inexhaustible. You'll need to manage it as you draw from it, maintaining intake while preventing depletion. Drain it all at once and you're back to the same problem."
"Fine. Your way, then. Let's do it properly."
Since it was already complicated, there was no point cutting corners. Build the whole thing correctly the first time and he wouldn't have to revisit it. Newt was the authority on purpose-built habitats and ecological balance in confined spaces; that consultation would happen before any ground was broken.
Tom left the learning space and stood before a mirror, carefully adjusting his appearance back to its usual state. Several hours had produced significant changes, and he wasn't ready to answer questions about them. He'd reveal the shift gradually, let people adjust to it incrementally. The goal was to avoid causing a scene.
Specifically, the goal was to avoid being descended upon by a collection of young witches who would disrupt his schedule entirely.
This proved optimistic.
The changes in quality he could mask. The shift in presence that the golden apple had left behind was considerably harder to suppress. It wasn't visual. It wasn't any one thing you could point to. It was the kind of change that made a room feel slightly different when you walked into it.
After returning messages to reassure the girls he was fine, everyone else settled back down. Daphne, however, arrived with Astoria in tow, clearly intending to ask where he'd been. That intention lasted exactly as long as it took her to get close to him.
Her nose twitched.
"Tom," she said, abandoning her planned question entirely, "you smell incredible."
She said this and immediately pressed her face against him and inhaled deeply.
"Sister," Astoria said, with the tone of someone witnessing an embarrassment.
Then she drifted slightly closer herself, took a quiet breath, and nodded.
...She had to admit it.
Tom looked between the two of them with resigned amusement. Were they under the impression he was a scented candle?
He deflected their questions with a convenient story and left the real explanation for later. The apple tree hadn't been planted yet, let alone fruited. Raising expectations before anything was confirmed would only create disappointment.
The following morning, Tom returned to the castle with both sisters, who had slept well and were in excellent moods. Hermione and the others noticed the change in him almost immediately. His status among the castle's population shifted in a direction that was, frankly, inconvenient. The looks he was getting were the wrong kind of attentive.
He stopped returning to his dormitory for the time being. The situation would calm down eventually.
After History of Magic, Tom climbed to the Astronomy Tower. Usagi descended from the cloud cover and nuzzled her enormous head against his cheek with the affection of an animal that knew exactly how large it was and chose to ignore the fact.
He played with her for a while before giving her the task: deliver the bloodline fusion potion to Grindelwald. He'd intended to hand it to Rosier the day before, but Dumbledore had kept him talking and he couldn't ask Rosier to wait indefinitely. A separate delivery it was.
"Fly slowly," Tom said, fastening the dragonhide wallet to Usagi's talon. "I worked extremely hard on this. If you spill it, I won't spend any time with you for a month."
Usagi bobbed her great head up and down solemnly in promise.