"You can either allow yourself to fade, and magic will take both you and that portion of Voldemort's soul. You'll eventually be reborn somewhere in a new life, but of course you won't remember any of this. That piece of soul over there doesn't have that choice, it will be removed from the great wheel entirely. That's part of the penalty for trying to split the soul as Voldemort did."
"And my other choice?"
"To return to life wherever your spell took you. I don't know everything about what you'll face if you do, the Powers-That-Be aren't that generous. But your life will be hard, harsh at times and fraught with danger. But I can also say that the rewards will be beyond even your imagining. She smiled warmly. I wish I could say you would find happiness, but that's another one of those choice things, all up to you really.
Harry very slowly pushed himself out of his mother's grip, standing on his own two feet in this wide expanse of white to stare at the vile thing that had been in his scar. "Was it in my scar, or was it in me, my own soul?" he asked almost absentmindedly.
"Sort of both." Lily replied with a wince, watching him anxiously, none of her own thoughts on what she wanted him to do showing on her face. "It was getting stronger all the time, as were you. Someone placed magical bindings on you. That kind of thing is normally done to children when they first exhibit their powers to stop them from doing so much accidental magic they hurt themselves. But the binding was slowly being, absorbed I suppose by that bit of soul, as well as leaching magic off you."
Looking to the side Lily frowned angrily. If only she had been able to watch more of her son's life, from right after her death rather than since the first time he had thought of her which was several years later. Then maybe she would know who that enemy was. She had suspicions, and coupled with the fact that she had seen Albus turn up and Obliviate not just Harry but a team of Obliviators made her even more suspicious of him.
But that in itself wasn't enough, since Albus hadn't said anything after and had indeed implanted memories in Dudley and his gang of bullies to make them stop picking on Harry. They hadn't held long, and he had never spoken to Petunia or Vernon, but was that simply absentmindedness or something more sinister?
Then there is the Will to consider. What happened to Sirius, The Longbottoms, or even Rufus? I don't really want to know how Harry would've turned out if Rufus raised him, he was a little too job and status-oriented to make a good parent, but he would have been worlds better than Petunia and her family of pigs!
Lily wasn't certain if Albus was conditioning Harry for some reason, or just was neglectful of what hiding Harry away from the magical world was costing her son, but she wasn't exactly happy with him whatever the case. She dearly wished that she was a real ghost rather than some kind of disembodied personality stuck following her son around, because if she was a ghost, she could go to Hogwarts and wring Albus' neck for what he was doing to her son.
While Lily was thinking about that Harry was thinking about what he had learned so far, and about the pros and cons of the two choices. In the end however his very nature rebelled against the idea of not taking up the challenge. "I want to go back." he said. "I want to see this new place I've found, maybe explore, maybe learn. I'm used to hardship, that doesn't frighten me and danger doesn't either not really. Not so long as I can fight back." he smirked and his fingers flex a little. "Will I have to hide my magic?"
"I don't think so, though I can't say for certain." Lily said smiling sadly if proudly at her son. Already the white area around them was fading as the Powers-That-Be had heard Harry's choice the instant he thought it. The thing that was Voldemort soul screamed as he began to dissipate, becoming so many little particles of darkness which then flared as they were consumed.
"I am proud of you Harry." she said, even as she felt the tug on her self/soul/body begin, pulling her back to where she had been before Harry had tried his desperate gamble. "Know that I will continue to watch over you, that I love you and that I am proud of you whatever you do with your life!"
At those words Harry turned suddenly, his eyes wide. "No!"
Lily felt his magical reach out for her, his soul connecting to hers here in this place. "Harry don't! It won't…"
"I don't care! I just got in my mother back, I just got a family back! You think I'm going to give you up, NO!" With every word Harry poured more of his willpower into his magic, trying to hold Lily's soul personality or whatever portion of her that was in front of him where it's was, trying to fight against whatever was trying to return her to the afterlife. His magic followed his desperate plea once more, slowly tying Lily's soul to his own.
Reality around them shimmered, then the white dissipated, and suddenly Harry found himself on a hard, solid ground much unlike the strange texture of the floor of the place he'd been just moments before. Various aches and pains told him he was still alive, and his eyes were crusted over, but even so his pains weren't nearly as bad as they had been, signifying that his healing ability had begun its work, though still had quite a bit left to do.
These new sensations made Harry realize that the only sensations he had really felt in that other place had been his mother's touch. With that thought his eyes popped open, and he looked around wildly "Mum?"