Clark started spending more time in the Arctic. With the cold he could not feel, the blinding white, and the unmarked, inaccessible terrain. With the endlessly bright days, the sun that did not set at this time of year. With the crystals of ice, and the crystals that made up the dwelling his parents had sent him here with. They must have known he would need it. Someday.
At first he would only stop in briefly before retiring for the night, but he found himself longing for it. He couldn't say how or when it happened. The shift as it occurred was subtle, perceptible only after it had grown for some time.
Until he noticed that, while getting ready to go out in the mornings, and during his days at the Daily Planet, and throughout his evening patrols, weaving amongst and between towers and skyscrapers, structures and buildings and places he used to see beauty in, he gradually and eventually started to change his mind. For more and more those structures and buildings and places started registering to him as at first, rather plain and simple, and then almost inconceivably dull blocks and squares, made out of at first utilitarian, then terribly inflexible materials, rock and stone, metal and glass, plaster and paint.
He was a little frightened when his descriptions, his assessments, those words started moving towards foolish, lacking, and finally, and perhaps inevitably: primitive.
Yet, a part of him wasn't. After all, this was not his planet, was it? Though he looked the part, he had very little claim to its culture, its developments, its customs. If not natural, then was it at least not understandable? That he could prefer the variety and intricacy of Krypton's crystals, its cones and its cylinders and the clear blue light that travelled throughout them? Over Earth's opaque cubes and pyramids and tented roofs?
Was it so bad that he wanted to wake up, and go to sleep, and spend his time there, and that, after awhile of fighting that impulse, with arguments that grew less and less convincing to him, about the importance of keeping his schedule, his routine, his life in Metropolis, that that is exactly what he did?
He still maintained his apartment, he maintained his job at the Daily Planet, he even would go out for drinks with colleagues after work on occasion. He maintained his duties to Metropolis as its resident superhero, his evening patrols of the city, and helped out during the day when necessary.
He had never been sure what to call that dwelling in the Arctic, only that it was his and it was personal, his retreat and a gift his enigmatic birth parents had bequeathed him.
Now, however, more and more, it became and he simply called it home. Home, where he more and more dedicated his free time to reading the vast stores of text and imagery and literature and history contained within it; this singular remaining vault, and ultimate depository of Krypton; the planet and its people.
When he briefly entered the Bat Cave, to pick up that shard of kryptonite, courtesy of Lex Luthor, and when Batman, masked and caped, had handed it over to Superman, he had, to Superman's surprise, asked if he had discovered anything in those files, about what had happened.
He answered honestly when he told him no. He had not.
He doubted Batman would ask again.
Case closed. Or more accurately, a cold case: unsolved and unknown.