Nineteen Years Later
I would dearly like to pretend that everyone was fine and dandy when the Potters' and Weasley's children got to Hogwarts.
The remaining Death Eaters who had, somehow, evaded capture, were angry. Angry that the boy who had thwarted their master for so long was allowed to walk free. Angry that he had named one of his children after a fellow Death Eater. Angry that they had lost friends, family and acquaintances alike because of this meddlesome boy.
So they devised a plan. To avenge all those who were thrown into Azkaban, to avenge those who had died trying to stop the boy from hurting their master, to bring justice to themselves for having to go into hiding instead of being captured for following their beliefs.
Oh, they would not kill the boy. They'd just take away everything that he held dear, just as he had done to them.
It took them years of waiting to have their revenge. They were going to act upon their idea a year earlier, when the first Potter boy entered Hogwarts, then they thought: why not wait until the Weasley brat went, too?
So, as soon as the Hogwarts Express left the station, they struck. To start with they Imperiused the driver, so the train could be stopped. Then, they attacked. They flew through the windows and doors, jinxing and cursing every child who attempted to stop them. There was no escape, all the children were trapped on the train that they so stupidly thought would be safe.
Their ignorance betrayed them. They had been brought up to believe that nothing was wrong. When they finally found the children they were after, they bound them and tortured them.
Meanwhile, back in London, Ginny Potter was killed when her and Harry were driving home. The attack was sudden, yet fatal: she was killed by the Killing Curse shot through the open roof, and as the Death Eaters flew away, they could hear, to their pleasure, Potters' wails of misery and grief.
Next, Ron and Hermione Weasley were attacked. They got back to The Burrow safely, where they were to visit Ron's parents, only to find the entire family slaughtered in the front room. The couple were then ambushed in the home, tortured for hours, and finally killed.
The Express reached Hogwarts, where another gang of followers took the Potter and Weasley children hostage, made them write a letter to Potter, them killed them.
The Dark Lord had finally been avenged.
Decades later, Harry Potter sat in his rocking chair at a nursing home, holding a photo of his family, the Potters and Weasleys, tears splashing on the laminated paper, while all the face grinned and laughed.