(A/N: I don't own Harry Potter. This is an AU of what might have happened had Severus Snape overheard Wormtail talking with the Dark Lord. It also makes an inherent assumption that he isn't evil!Snape. This is the Snape who still wants his only best friend to live, even if it means losing her to another man.)

It was a rather chilly, stormy night. The pounding rain and frequent thunder erased any trace of sound outside, as well as thoroughly drenched anyone crazy enough to step out on a night like this. Severus Snape knew better than to assume no one would be out on a night so tempestuous. Weather like this provided excellent cover for missions of utmost importance. It was rare for anyone to even peek out the window of any of the cheerfully lit houses or to take note of anything seen. Comfort was far more important for both Muggles and wizards alike than curiosity. Still, he clutched his cloak tightly in a failed effort to keep the rain from drenching him further and hurried up the quiet street. His destination was quite a bit further, yet he did not increase his pace. He was a man on a suicide mission. If the Dark Lord had any suspicions of what he had planned, Severus would have been killed already. Then again, the Dark Lord likely had no idea of what he had overheard. It was a mere accident that Severus had been at headquarters earlier that night, but a raid the previous night had forced him to place one of his experimental potions into stasis. If he had only finished his potion last night, the already cracked and warped foundation of his loyalty wouldn't be shattering into pieces with every drop of rain, in danger of being swept away by the second. The dark night had gone fragile.

The icy rain was making his anger cold and sharp. No matter how hard he tried to occlude his mind, he couldn't block it out. He couldn't push away the tumultuous betrayal. They had promised that Lily would be safe. He had told Voldemort about the prophecy hoping that going after two of the top Aurors would get the Dark Lord killed. Hell, they'd even taught Moody a thing or two about paranoia and booby trapping. He doubted that Voldemort would have even made it through the front door. It didn't even cross his mind that the Potters had thrice-defied the Dark Lord until after the prophecy had been relayed. They might have hit the third time just after. It didn't matter anymore. He thought he had persuaded Dumbledore to move the Potters far away, preferably in a fortified manor behind a layer or six of wards. After tonight, he knew they hadn't been. They were as far from safe as imaginable.

He strode up to the house at the end of the street and stalked up the sidewalk before precisely rapping on the door, using the methodical knock that was trademarked to those in the Order. After a minute, the door swung open and Sirius Black looked out, his body preventing the door from opening further. His wand was pointed straight at Severus.

"Give me one good reason why I shouldn't kill you, Snivellus," Sirius snarled.

"Because Lily is in danger," Severus said softly. Had it been any other night, he would have snarled as well, but not when she was in danger.

Perhaps it was the words, or something in the way he'd said it, but Sirius took a step back, looking pale. Before he could react, Severus raised his right hand, index touching middle finger and ring touching pinky.

"I, Severus Snape, solemnly swear on my life and magic that I have not come here tonight with the intent to physically harm Sirius Black in any way. So mote it be."

The gold mist fluttered around him, marking the man in the doorway as witness. That man was currently staring at him with a shocked look on his face.

"I guess you'd better come in then," Sirius said, opening the door and waving Severus in.

"What's this about Lily being in danger," Sirius asked, after closing the door and snapping up several privacy wards.

"You aren't the secret-keeper," Severus said, knowing the answer but still hoping that the man in front of him would deny his statement.

"No I'm not."

"Pettigrew is, correct?" He willed the fates to have it any other way.

"How'd you find that out?"

Severus felt sick.

"I stayed late at the lab tonight, working on a time-sensitive project," he told Sirius dully. "I'd expected to finish it earlier, but one of the new recruits had invariably contaminated it. I had taken a break when I came across Pettigrew conversing with the Dark Lord. I'm not sure what all he shared, but he told Voldemort where the Potters live. We have to get them out. Now."

"Was Voldemort torturing him? We had him hidden!"

"No. He is a Death Eater. He called the Dark Lord 'Master'."

While Severus was talking, Sirius rushed around grabbing his dragon hide combat boots and his battle robes.

"Not that I care, Snape, but why are you telling me this?"

"Because of Lily. There are quite a few at the ministry who aren't loyal, and I can't be certain that Dumbledore would act on this until too late. I have no idea where Remus is currently. You were the only other person I had an address for."

"Let's go," Sirius said, grabbing Snape's arm before twisting him through side-along apparition.

They arrived outside the cottage where the Potters were staying. Children were roaming the streets, dressed up in various costumes. Nothing looked out of the ordinary. They drew their wands and started toward the house; Severus was glad that this was the one night where their attire and their wand usage wouldn't draw any unwanted attention. The Muggles were willing to believe anything on Halloween. Severus started as someone kicked a pebble; he spun around to find a little kid dressed as a ghost tearing down pavement to the next house, his white sheet trailing out behind him. Severus relaxed slightly, annoyed at himself for being startled by a child. Sirius finished checking the perimeter, before sighing in relief.

"Good, we made it in time. I'd…"

And with that, pandemonium erupted. Two twin green flashes ruptured the darkness. Severus doubted he would ever forget just the way it had streaked his vision as he realized in muted horror that the green could only be from a killing curse. The flashes were merely the lightning before the thunder. The explosion roared out from the darkness, swallowing them both. The windows cracked and part of the roof blew off, raining the street below with rubble. The worn teddy bear landing at their feet shocked Sirius out of his stupor. He sprinted forward, racing into the wrecked cottage. Severus wasn't far behind, though he knew what they would find inside. Death, and quite possibly the Dark Lord. Oh Lily.

The scene in front of them wasn't pleasant. James lay partially blocking the staircase. Sirius was looking in abstract horror at the body of his best friend, but Severus didn't pause. He moved up the stairs toward the destroyed room. Everything must have culminated there. He reached the room to find the stars staring back at him. With that much damage, they were lucky the walls were still standing. He looked around, wand outstretched, only to give an anguished cry. Oh Lily.

She was crumpled in front of the cot, eyes forevermore wide open. He knelt and cradled her body to his chest, sobs racking his body. Gone was his best friend. Gone was the girl strong enough to rand up for what she believed in, even to him. Gone was the girl who showed him the magic in life when he'd been convinced there was nothing but darkness and pain. He vowed that he would never let anyone forget the vivacious girl she'd been, the wonderful woman she'd transformed into. Oh Lily.

He caught a hint of movement directly behind him and turned to see Lily's son standing in the cot, the tear-streaked green eyes peering down at him. Severus gasped. Those eyes… Why did genetics have to give him her eyes? Unconsciously, he reached out and let the side of the cot fall, pulling the infant into his arms. There was a gouge on his forehead that needed to be treated, but for the moment, Severus simply watched as the infant squirmed a bit and reached out a small hand to pat his mother's cheek. He choked back a sob. He had no idea how the infant survived the encounter with the Dark Lord, much less the following explosion.

Had the world been different, he might have stayed Lily's friend and might have met her son before tonight. It was curious that the boy had even survived, but the wand and robes heaped a few paces away gave evidence that the Dark Lord had not survived this particular encounter.

Severus could hear footsteps thundering down the hall long before Sirius appeared in the room.

"Harry's alive?" Sirius asked, reaching down and scooping the toddler into his arms. "Oh thank Merlin, Harry's alive!"

"We need to get out of here," Severus said suddenly.

"What?"

"Use your brain, Black. The house just blew up. The Muggles are certain to call the police, and the Ministry won't be far behind. Does that mean nothing to you?"

Sirius paled.

"They all still think that I'm Lily and James's secret keeper."

"Precisely. Most will believe that I am strictly a Death Eater, as well."

Severus stood up and began gathering items. A quilt, a dog-eared book, formula, bottles, a few toys. He grabbed whatever would be necessary and most of what was on the changing table, before shoving it into a baby bag.

"You aren't a Death Eater?"

"I am, but I'm a spy as well."

"Who all knows? And why?"

"The why will need to wait until later, but both Albus Dumbledore and Alastor Moody know."

"Mad-eye Moody? And he didn't kill you?"

Severus flicked his wand, summoning various items from around the house. He surveyed the rest of the room. They would need a new cot; the one in the corner had been cracked at some point.

"I've been attending Order meetings under an invisibility cloak. Moody can obviously see through cloaks and wouldn't believe Dumbledore until he questioned me himself. Grab everything that you think is important. No doubt there will be looters here at some point, perhaps before we can return."

He bent down as they left the room, carefully pulling off Lily's wedding ring and jewelry. No doubt her son would want it some day. He put it in the bag, before brushing a kiss to her forehead. It would likely be the last time he saw her. He stood, only to find Sirius staring at him oddly.

"After all this time?" Sirius asked softly.

"Always," Severus responded stiffly. "Always."

They continued down the hallway, with Sirius stopping to grab certain items and summoning others. They headed down the stairs, only stopping to grab James's ring and watch.

"Goodbye, brother,' Sirius said mournfully as they walked out of the house.

Severus scooped the forlorn teddy bear out of the street, before turning to Sirius.

"You've been to Lily's childhood home, correct?"

Sirius nodded.

"Apparate there."

In a swirl, they both were gone. It would be nearly an hour before the Fidelius Charm had degraded enough to allow others to see the wreckage of the home. Only the muggles who had witnessed the blast could have seen it before then. By that time, Hagrid showed up to fetch young Harry and was waiting outside. The Headmaster had loaned him Sirius Black's bike, hoping it would make everything easier. As the wards finally crashed, Hagrid stalked in through the rubble. He had strict instructions to bring Harry to Headmaster Dumbledore. He would know what to do with the tyke. Hagrid sobbed as he passed the fallen bodies of the Potters. He couldn't believe that they were dead. At least the wards had indicated Harry was alive.

However, Hagrid was shocked when he reached the cot. Harry Potter wasn't there. He hurried down the stairs, which nearly didn't hold his weight the second time. The Headmaster needed to know about this. A quick flick of a pink umbrella ensured that the muggles wouldn't be bothering the house. With that, Hagrid portkeyed back to Hogwarts, intent on reaching Headmaster Dumbledore. Surely he would know what to do.

(A/N: One aspect needs to be noted- Severus overheard the address of where the Potters lived from Pettigrew, enabling him to see the house as well. Some of the back story will be explained in the next chapter. That chapter will be up Wednesday.)