DISCLAIMER! I DO NOT OWN HARRY POTTER!
This will be a Powerful!Grey!Harry Story. I don't know pairings yet, however they will (mostly) be straight. Harry at least will not be bi/gay. Nothing personal. I will say this, I don't plan on bashing any characters. If I have two ways of interpreting a character - as powerful or as stupid, I will choose powerful. So (For a canon example) - Voldemort was not stupid for wasting a year in the fourth book when he could have simply portkeyed Harry during a Hogsmeade trip. Instead, he was smart as the ritual had to take place on midsummer's day, it as strengthed by harry being a 'champion,' Dumbledore has blood-tracing magic placed on Harry so he would have been able to find him, the ritual involved far more than the ingredients we see, we only saw the final stage, etc.
So yes Harry will be powerful. Just expect Dumbledore to be more so, and for Voldemort to be a terror. On the same lines though. Harry will be smart, just expect Dumbledore to be smarter (albeit busy and getting old) and Voldemort to be an evil genius (albeit without most of his soul and having spend a decade as a wraith, so not all there).
Prologue.
Harry was always told by his relatives how his mother and killed his father and had been sent to prison for it. How she had both been freaks, and she eventually snapped. How they had been unemployed, drunkards, and wastes of space.
He would have believed them, if not for his nightmares. Ever since Harry was young, he had always had one recurring nightmare.
The room is a nursery, but it's covered in a bloody red haze. A dark snake-faced man steps in. A man stands in front of Harry, blocking his view. "You cannot take him," he says, his voice defiant and strong.
A high sibilant voice answers "You cannot stop me Potter, step aside and perhaps I shall let you live."
"Never."
"So be it. Avada Kedavra!" A green flash, and Harry's protector crumples. The killer walks forward, a distorted face looming into view. Then, two final words. "Avada Kedavra." Only this time the light is no green flash but an explosion of blood red fire. Then, the killer is gone. A red-haired woman runs in. She almost crumples at the sight of death, but runs to Harry.
Darkness.
Then, the woman being taken away, dragged away. Accused of murder. And Harry is in the arms of an old man who promises to care for Harry.
And then Harry wakes up. In a the cupboard under the stairs at Number 4 Privet Drive.