Disclaimer: I am not J.K. Rowling. I do not own Harry Potter.

Note: The following alternate universe one-shot is a rough sketch posted in the hope that it maybe encourages someone else to take the idea (or one similar to it) and to run with it. It's not exactly a polished piece. This piece is rated as 'T' and is identified as 'Tragedy'.

Sirius Black had meant to blow Peter Pettigrew, that nasty little traitor, to smithereens, of course, for betraying James and his family; he just hadn't expected half the street in the muggle area he'd cornered Wormtail in to explode, too.

Perhaps that had had something to do with that hole in the street behind Peter?

There were multiple muggles lying around dead or horribly injured.

It occurred to Sirius that he'd done something absolutely ghastly, but something that his parents would have been absolutely proud of; he started to laugh at the insanity of it.

He was still laughing crazily, when the other witches and wizards arrived.

He was still laughing hysterically, when they sent him to Azkaban.

Dedalus Diggle was a wizard in a hurry to get out of the country.

He was in a hurry to get out of the country before anyone discovered what he'd done.

He wasn't particularly proud of himself or of what he'd done: he'd been captured by Death Eaters and made to swear an unbreakable vow by Lord Voldemort himself to provide the Dark Lord with one thing – a note revealing the Potter's location, such as might be obtained from the Order, and without Dedalus giving warning what he was doing to anyone beforehand or for twenty-four hours after he'd delivered said note to Lord Voldemort.

Dedalus Diggle had betrayed the Potters, to save himself from the tortures that otherwise might be inflicted on him, and of which he had been given just the slightest foretaste.

Soon the Order would be questioning the man known to be the Potter's secret keeper, Sirius Black, about how the Potters could have come to be attacked. And then the investigation into the notes would commence, and somehow – with Albus Dumbledore in charge of the investigation – Dedalus just knew that culpability would be traced to him.

And if Dedalus had been terrified of what Lord Voldemort might have done to him, whilst Dedalus had been in his hands, he was at least as scared of what the only wizard who had ever given Lord Voldemort pause would do to Dedalus if he got his hands on him.

No, Dedalus needed to disappear – preferably right out of the magical world and a long way away from Britain.

Albus Dumbledore was relieved that the war was over at last, though the cost had been terrible. Even in the last throes, the Death Eaters were committing terrible acts. Sirius Black, unmasked at last as a traitor, had gone to Azkaban, having committed one final crime of mass-murder; someone had killed Alice Longbottom and left a 'dark mark' above the house whilst her husband was out, trying to help clear up the mess that Sirius Black had created; and now it seemed that poor Dedalus Diggle had vanished without a trace. The war seemed to have been getting to poor Dedalus in the last few days. Albus had meant to have a word with him to find out what bothered him and to offer to perhaps help, but now he almost certainly never would. Dedalus' was going to be one more name that would be added to the list of those who would likely remain forever-missing victims of this war…

Author Notes:

I wrote this originally, because the idea appealed to me of a completely out-of-field minor character of canon having been the one to betray the Potters' location to Voldemort.

Basically the idea is that up until shortly before Hallowe'en 1981, events go roughly as in the original timeline, with the exception that Peter Pettigrew does not come under any kind of Death Eater influence whatsoever, but another Order member, a few days before Hallowe'en (Dedalus Diggle in this case) does.

With the Potters dead Sirius draws the same conclusion that he apparently does in canon that the secret keeper must have sold them out and goes after the (in this universe, completely innocent) Peter. I suspect that Sirius would at the least try to seriously harm Peter, given his likely state of mind (Sirius feeling betrayed and angry) and would 'shoot first'. The street being dug up and Sirius taking out a gas main and blowing Peter and umpteen muggles to bits is a piece of artistic license, though I consider some sort of over-the-top result probably necessary for any ongoing plot that would require Sirius being in Azkaban (so as not to be in Harry's life, for example).

Lord Voldemort left Dedalus at liberty but unable to warn anyone in case something went wrong with his attack on the Potters, and Lord Voldemort needed to round Dedalus up and put the screws on him to gain more information from him.

Dedalus goes on the run without realizing that Sirius has taken the blame for betraying the Potters. He's likely to remain out of contact with the wizarding world for some time, reducing his chances further of hearing the news.

I've taken the liberty of assuming that occasionally Order of the Phoenix members have gone 'missing, presumed dead', to explain why Albus doesn't bother himself about Dedalus' disappearance.

The Lestranges went after the Longbottoms, but Frank got a 'lucky break' this time, being out 'on call' when the Lestranges came around. With only one Longbottom adult to hand Bellatrix went so far as to torture Alice to death. With the capture/interrogation of various Death Eaters likely progressing as in canon, the Lestranges will be eventually identified as being responsible for the death of Alice Longbottom, and duly sent to Azkaban. Neville Longbottom gets brought up by his father and has a better upbringing than canon. (Harry Potter, of course, is in a worse situation than canon at some point down the line, as his godfather genuinely has murdered an innocent wizard...)

As mentioned in the opening notes, this is a one-shot, posted in the hope that maybe someone else will take the idea (or do something similar) and run with it.