Disclaimers: None of its mine. All belongs to J.K. Rowling.

October 31st 1986

Remus knew something was wrong. He'd known from the minute he apparated outside Peter Pettigrew's house that something wasn't right. There was no tangible reason for this belief, but his senses screamed it at him. 22 year old Remus Lupin had been an auror since graduating Hogwarts and he hadn't survived four years fighting in one of the bloodiest wizarding wars in history without developing certain instincts.

Then again, he'd always had a good instinct for danger. An unexpected advantage of being a werewolf.

He pulled out his wand.

Moving more silently than any human could ever aspire to, he approached the house.

It wasn't supposed to be him here tonight. Sirius had been supposed to come, but his auror group had been called to Devon to investigate a suspected Death Eater meeting. Sirius had returned just one hour previously, exhausted. Remus wasn't supposed to be working that night but, seeing his friend's weariness had volunteered. There weren't many people who could take on this task, because there went many who knew why it had to be done.

At the start of the war the ministry had assigned aurors to those they believed were at particular risk but these days they were simply spread too thin on the ground to do this and alternative solutions had to be found. Lily and Harry Potter were amongst the first to hide using the Fidelius Charm. Lily had tried to persuade James to hide as well but James was an auror, and a talented one and hiding whilst others fought was simply not in his nature. It wasn't in Lily's nature either but Harry was her first priority so while he hid, so did she.

It had common knowledge that Sirius Black was the Potter's Secret-Keeper. It was also wrong. After a lot of debate that job had been given to Peter Pettigrew. Remus had to admit it was a decent bluff. No-one would suspect Peter. He was not an auror, unlike Sirius. He was not even taking an active part in the war, choosing instead to work at the Magical Menagerie in Diagon Alley. He was, if not a fence-sitter then at least an abstainer, believing like so many others that if he did not fight, Voldemort would not target him. Volunteering to be the Potter's Secret-Keeper was his one brave act since leaving school. Remus always tried to see the good in everyone but he had fought too long, and seen too many good people die to have much patience with those who chose not to pick sides, those who allowed others to die for them but would not make a stand themselves. It was an attitude shared, he knew by James and Sirius and over the last few months the strain had begun the show on the once close group of friends. The harder Remus, Sirius and James fought against the darkness the harder they found it to sympathise with Peter's self imposed ignorance. Remus hated feeling like this, especially towards someone he considered a friend but the fact was, the Marauders were strained to braking point. It was for this reason, Remus suspected that Peter had volunteered to be the secret keeper. It was relatively low risk, since the whole world save Sirius, Remus and Dumbledore believed Sirius was the Keeper, but it was allowed Peter to ingratiate himself with his friends.

And so, two nights previously Peter had been entrusted with the lives of Lily and Harry Potter. And Remus and Sirius had been assigned to look after him.

Remus had been present when the spell had been cast; he'd been working, but James had sent him a note telling him everything had gone well. Peter had taken Lily and Harry into his soul, and then divulged the secret to James, allowing him to see his wife and child.

For two days nothing had happened. Sirius, James and Remus had kept a close watch on Peter but no-one seemed to suspect.

As he entered the house though, Remus was forced to conclude that that was no longer the case. Peter was gone, that much was clear. Remus' sharp mind raced through possible options; contact James? Sirius? The Ministry? Dumbledore? But even as he thought this other things started to become apparent to Remus. There were no signs of a struggle. Surely even Peter would have fought back? He had enough warning- there were wards around the house. Remus forced himself to concentrate, feeling out to the wards, testing their strength. They were fully intact. This meant, Remus realised with horrible clarity, no-one had come here and forced Peter out, he had left of his own accord.

Traitor.

The word flashed across Remus' mind even as he prayed he was wrong. Prayed there was another, innocent explanation for what he was seeing. With no thoughts of calling for help, nor of the danger he could be heading for, Remus apparated to Godric's Hollow.

The house was rubble and the Dark Mark floated above it. Remus ran across to it and began searching through the wreckage. His heart nearly stopped when he unearthed the body of Lily Potter, beautiful even in death, her green eyes staring glassily at the sky. Remus gently lifted her and carried her out of the rubble, laying her on the grass beside the house.

When asked later Remus would not be able to say how long he sat their, looking at Lily's body. He knew he should look for Harry and James but his grief was already to great and Remus thought if he found the body of that beautiful baby boy, not to mention his best friend, his heart would surely break. So he hung onto his ignorance for just a little while longer.

A noise from behind Remus startled him out of his thoughts. He turned and was shocked to see James, holding Harry.

Remus, whose brain had shut down on finding Lily, was now fully alert again and thinking fast. He could see Harry and Lily, which meant that Peter had not only betrayed his secret to Voldemort, but removed the charm altogether. Harry was exposed and at risk. At any minute aurors would start to arrive and right now Remus trusted no-one. He had to protect James and Harry.

James had seen Lily now and he moved forward and unsteady legs towards his wife, dropping down at her side. Remus didn't think he presents had even been registered yet but James became aware of him moments later when Remus reached out and, lying a hand on both James and Harry whispered, "Fidelius animus"

Just a couple of notes:

Fidelius means faithful or loyal, and animus means (among other things) soul. I don't think the Fidelius charm appears anywhere in the books so this was the best I could do.

Also, you might be wondering why James wasn't SK, since he knew the secret. According to ( I think) Wikapedia only the SK can divulge the secret so, even if he was caught and tortured he could not betray his wife and son. I assume this is true, but if not, this story is AU anyway so it doesn't really matter.

Anyway, thanks for reading. Hope you enjoyed it. Feel free to review.