Disclaimer: Trust me, I don't own Harry Potter. If I do, at any point, acquire Harry Potter, you'll be the first to know.
Voldemort strode through the remains of what was once the door to the Potter household and cast a quick charm to determine the presence of its usual occupants. The spell released an innocuous puff of smoke and the Dark Lord smiled. His wards would stop any petty attempts at escape from the family he now knew to be inside, and guarded against any possible rescue from the outside- he had been plotting this night for some time.
There was no chance of survival.
He happened across the first annoying Potter as soon as he entered the kitchen, the only available entrance to the upper floor, where he assumed the rest of the family were cowering. As if hiding would protect them from him!
The scruffy-haired nitwit brandished his wand like a fencing foil- the cretin- and spouted some obviously Griffindorish nonsense that Voldemort summarily ignored. A killing curse took care of him- no use wasting time on an ultimately pointless duel-and-torturing session, no matter how fun; he had work to do.
Leaving the man to cool on the tiled floor, the Dark Lord stalked (he would never lower himself to merely walk) up the tastefully grey carpeted stairs and posed dramatically at the top, looking as out of place in Muggle suburbia as Petunia Dursley would in Founder's era Hogwarts.
He could hear now the heartbeats and low breath of two people- one obviously belonging to a small child- in a room four feet forward and to the left of him. He smiled; the expression as cold and unwelcoming on his face as a slug in a bowl of punch.
He casually blasted down the flimsy door (and the multitude of exceedingly powerful wards that had clearly been put up in a hurry) with a negligent flick of his hand, then bore down on the terrified mother-and-child before him.
The woman (Lily Potter, mudblood) stood, and raised a shaking hand, but didn't cast.
Lord Voldemort briefly considered dispatching her for her impudence, but then remembered what Severus had requested of him in return for the information he had received. He toyed with both ideas for a piece of a second, then decided to keep the girl. It made no difference to him, and risking a man with potential as great as Severus' to the chance of betrayal was silly for such a small effort. He only wanted the boy, anyway.
A quick petrifaction curse (she would be fine, and easier to move later), and the girl was frozen in place, leaving the now squalling child utterly defenceless. This boy was supposed to defeat him?
He stepped round the prone figure of the redhead to a perfectly normal cot. The 'loving' parents hadn't even bothered to place any wards or enchantments to stop evil wizards like him doing exactly what he was about to do.
The black-haired toddler in front of him was standing upright and crying profusely whilst rattling the bars of his cot. Voldemort raised his wand, then paused as he considered exactly which curse to cast. The Killing curse sprang to mind immediately, of course, but perhaps it wasn't best to fire a volatile spell which could cut through all enchantments (such as the ones placed on his clothing, to prevent any... mistakes) and kill without warning into the cot of the one who was said to be able to defeat him.
He determined quickly an array of spells to use, but paused first and created a portkey to his dungeons, attached it to the girl and set it off- no point in damaging her if there was any magical backlash. He then proceeded to cast a barrage of offensive magic at the child, starting with simple cutting curse and increasing steadily onto high-level dark arts hexes.
After the smoke cleared (with a helpful hand from Voldemort), nothing but a slight mess of blood and some splinters was present. Harry Potter was dead.
The Dark Lord checked, briefly, with a plethora of spells to verify the boy's fate, and confirmed it with a chilling laugh. He disappeared from the scene in a cloud of shadow, the echoing laughter the only evidence that remained of his prior occupation.
Voldemort went on to destroy the Longbottom boy and his family easily, the lack of need for the survival of an occupant meaning that he could just blow up the place, and blow it up he did.
Five months later, Dumbledore was dead and wizarding Britain under his command.
A year later and the entire world bowed before him.
Two thousand years later, and long after the names 'Tom Riddle' and 'Harry Potter' ceased to have any meaning, a mighty Dark Lord was vanquished by one marked to be his equal, and an ancient prophecy fulfilled.