"You have a visitor."

Looking up from the little hell-hole he'd spent all his time in since he'd been killed upon the earthly plane, one Tom Marvolo Riddle raised an eyebrow at the figures before him.
The first and foremost, the very one who'd just addressed him, was of course, Death. The cloaked figure stood ten feet tall, towering over the two accompanying him, powerful, imposing and menacing. Exactly how he'd been when he'd first met Tom at the passing between the mortal plane and this hell hole he was currently stuck in. It hadn't laughed at him, but even laughter would have stung less than the silent, smug superiority that he'd been given. It cut deep, that he'd still been unable to avoid death no matter how hard he'd tried.
Still he'd ended up here, with his mind slowly driving him mad. The desperate need to prove he was more than just another trapped soul in the eternal workings of this realm persisted. If Death had a face, it was probably sneering at him.

So Tom looked away from the figure, turning his attention to the others.
The first, the taller of the two, took him a moment to place, but when he did, he laughed. Gellert Grindelwald stood, an angelic faced eighteen year old. Blond hair that curled only ever so slightly at the end, an almost frozen quality to it, along with his icy blue eyes. Yet he seemed infinitely amused at something. Oh, of course.
Tom laughed bitterly as his eyes landed on the final person, shaking his head back and forth as he did so.

"Come to gloat?" He asked, watching as Harry Potter ran a hand through his hair. He too looked no older, the same age as when Tom had last seen the boy, who just stared back at him with the piercing green eyes. But, Tom wasn't too disappointed; he'd been here too long to hold onto old grudges. Well, maybe. The slightest burn of annoyance still remained. Most of his anger was at Death itself nowadays.

"No. Listen, when I hit forty, some huge volcano in American erupts and wipes out almost all the population of earth, both magic and muggle kind alike. I've lived twelve lives so far, trying to stop it and each time I've messed up." Sitting down on the floor in front of him, Harry took his glasses off and rubbed at them, absent-mindedly patting the spot next to him. And with little hesitation, Gellert sat beside him, still wearing the cocky smirk that'd graced his face since Tom had first laid eyes on the teenaged dark-lord.

"Death keeps sending me back, and I've been allowed to pick some people to help me out each time. The first few, obviously I went with some of the lighter side people, but that just wasn't working. To be honest, it's gotten to the point where I've just stopped caring how I get the job done now, as long as it gets done. Gellert's already agreed to come give it a crack. Are you in?"

And Tom laughed.

Because, oh, wasn't in ironic, that he was being asked to come and save the magical kind that he'd once wanted to rule over, to dominate. That his enemy was asking for his help, and didn't seem too bothered about how they'd get the job done.
Oh of course the boy wouldn't allow for the deaths of innocents, even living so many lifetimes, his core characteristics would still remain the same. Tom wasn't stupid, he knew he'd be working with a boy that would want to save everyone he could. In all honesty, it was a choice between going and helping the brat -who really couldn't be considered a brat anymore if he'd lived twelve lifetimes- or remaining here. Go and run around the mortal plane for a bit then return, or just stay put?

Well, it wasn't exactly the hardest decision of his life. But-

"What's your plan so far?"

"Find and raise Atlantis."

At his raised eyebrow, Harry shrugged nonchalantly.

"It was used by our kind the last time that blasted volcano erupted, I've managed to find that out. You two are suppose to be geniuses or something like that, and I know you've got the power to back it up. If this try doesn't work, I'm asking for Gryffindor and Slytherin next time."
The green eyes looked over to Death, and Tom got the vaguest sense that the being was amused.

"Of course Master," the sharp, raspy tones of his captor filled the room again and Gellert cackled, looking mightily pleased at the title that Harry had just been addressed with.

"So, you in Riddle?"

"A choice between remaining here or going to torment Dumbledore and his blind followers? Do you even need to ask?"

So, this is going to be my first big Harry Potter story, and by big, I mean well over 100,000 words is what I'm aiming for. With big chapters hopefully. I pray at least; the idea was too good to pass up. As for the FemHarry bit, Harry has been born 12 times, and not all of them has been into male bodies of himself. This is gonna be one of those times he's just in his female body. So, yeah.

By the huge volcano, I'm referring to the supervolcano beneaht Yellowstones -go 16 year old Geography knowledge- that, if I remember correctly- is overdue a blow. Hence my story idea.

Not too sure about pairings yet, not my main priority.

Thanks for reading this very short prologue.