After the Christmas holiday began, Linley set about searching for the Mirror of Erised within Hogwarts Castle. However, he did not know the exact location of that abandoned classroom. It took him three days—and even then, he only found it by following Harry, who had made a tremendous racket.
Unfortunately, the moment he arrived, he noticed Professor Dumbledore sitting on a table. This forced him to obtain Professor Dumbledore's permission before studying the Mirror of Erised.
"Oh?" Professor Dumbledore said softly. "But I believe you understand the dangers of this Mirror of Erised."
Linley nodded. "Naturally. I have no interest in what the Mirror of Erised reflects, but it is an exceptionally exquisite alchemical creation. I wish to borrow it to study the mysteries of the alchemy within it."
"You should know, Professor, that I have already taken Professor Green as my master. I am now a formal alchemist," Linley told Professor Dumbledore.
As the headmaster of Hogwarts, there were naturally few things that happened within Hogwarts Castle that could be concealed from Professor Dumbledore. Linley believed that the other man had long known he was Professor Green's student, so he stated his intentions plainly.
Professor Dumbledore was not surprised. An imperceptible glint flashed behind his half-moon spectacles, and he nodded slightly. "Of course. Hogwarts never refuses students who wish to learn more knowledge—except dangerous knowledge. You may study the Mirror of Erised here, but only tonight. I will still move it away tomorrow."
Linley had no objections. He also understood what the Mirror of Erised would be used for.
At the end of this school year, the Mirror of Erised would become the final safeguard protecting the Philosopher's Stone. Only someone who wished to find the Philosopher's Stone but had no intention of using it could take it from