Summary:

Tony's finally destroyed the world through a zombie apocalypse. Y/N, back from saving the universe, loses her memory in a freak accident. Now, with no idea what the heck is happening, Y/N must save the day while running from an obsessive, crazed Captain America and trying to stop the new world order Iron Man has established. Will she be able to save the world? Will she regain her memories? Will she ever find a decent pair of shoes…?

I'm gonna level with you- this is gonna get sappy at times. Lots of angst, so grab something stable and hang on.

-0-0-0-

Chapter 1

Steve had always known that Tony would one day do something that the Avengers couldn't clean up after. It was practically inevitable, in his opinion. He just hadn't thought it would be this soon.

It all started with a Hydra super weapon they had recovered. Tony, of course, wanted to reverse engineer the thing, which appeared to be a virus, to see what it was. He wanted to experiment with it on rats, learn how it worked.

"If we know how they make it, we can use that to keep an eye on suppliers of those materials and find out if anybody tries to make it again," Tony had pleaded with his friends, trying to make them forget the whole Ultron fiasco. "And if I can learn how it works, I can find a cure and counter it! What if they made more? What if they're already planning to drop it on some highly-populated area? The deaths will be on our heads then if we don't learn about this thing," he had urged, circling the room nervously.

The Avengers had finally relented. Retrospectively, they should have been more hesitant about letting Tony do something like this on his own. If Banner had been there, maybe this wouldn't have happened.

If She had been there, undoubtedly none of this would have happened.

Steve wished desperately that She had been there. Every time something had gone wrong, She had known it was coming and warned them. The times She couldn't warn them because their ignorance would save more lives in the long run, She put herself directly in harm's way to save the lives that She could. If She hadn't been off in God knows whatever other dimension at the time, Steve knew with no uncertainty that She would have fixed this, prevented it somehow. Instead, he was alone in this desolate wasteland, friendless and hungry. What reason could he have to go on? He settled into a pile of rubble to sob, sob like he hadn't since the painful early days.

-0-0-0-

One Month Prior:

"What have I done…" Tony mumbled to himself as he surveyed the horrible scene.

Zombies.

Who would have known?

Me, he reminded himself. I would have known. I SHOULD have known, he corrected himself. I should have known and I screwed this up.

It had been a simple mistake. How could he have known the consequences? Long hours of slaving over this formula had been unfruitful. He got angry, he got careless, he had dropped the vial. To his horror, the fluid within instantly vaporized at the impact, creating a much larger cloud of sickly yellow fog than should be possible, given the small size of the vial. He tried to close the windows and doors, to seal the virus in with him as long as possible. What he forgot to do was to turn off the ventilation fan.

"No! NO!" he cried, tripping over a table of beakers as he tried to reach the off switch. Pointless. By the time he turned off the device, all the fog had been sucked out into the open air. He couldn't be responsible for more lives… not after Sokovia…

He slapped himself a few times and turned himself back to the work bench. After exposure to such a concentrated form of the virus, he diagnosed himself with hours to live. He had to find the cure for when the released virus cloud started taking effect. Downtown New York wouldn't know what hit them, and Tony wasn't about to let his stupidity destroy the world… again.

-0-0-0-

Y/N knew, upon stepping out of the portal, that something terrible had happened. She thought back to the movies. According to the Stone, it was just after the events of Age of Ultron. Nothing should be happening now, except for a few minor issues. The world shouldn't be in an uproar like this.

And yet, it was. Hordes of people flocked to the streets, screaming. Children stood crying, having lost their parents in the rush. Suitcases lay open on the ground, shop windows had been smashed and were in the process of being smashed. Chaos.

Y/N immediately began to worry for her Avenger friends. Nothing good ever happened to them at times like this, especially when the problem was something unscheduled, something that wasn't in the movies from her dimension. The immortal tried harder to remember if something was supposed to happen, perhaps she had only forgotten.

Whenever the Stone made her dimension-shift, her memory of the past dimension always went a bit hazy. Every jump further clouded her memories, to the point where she could only remember her adventures for three dimensions back, and barely remember that even.

But this dimension was her home. The Avengers were her family. Through sheer willpower she had retained most of the memories, and as she finished delving through the depths of her mind, she concluded that she had not forgotten anything. This wasn't part of the movies. This was bad news.

The moaning in the distance amped up its volume. Y/N hadn't noticed that before, but now that she listened carefully, it sounded terribly familiar…

A bloody, mutilated figure appeared down the crowded street and began tearing into an unfortunate woman. As an icy jolt ran through her heart, Y/N realized that it was a zombie. Impossible!

She leapt into action, pulling her handy knife from her belt. Using her enhanced strength, she skewered the undead attacker through his skull, pleased to see that it immediately went limp. These work like the Walking Dead zombies, then. That's good, I've dealt with them before, she nodded to herself, memories of her time in that dimension becoming more clear. She turned her attention to the woman on the ground.

Her throat was shredded clean through, there was no way this lady was alive. Y/N looked around at the terrified crowd, all of whom were fixated on the gory scene.

"You should all probably stay inside. Stock up with some food and water and lock your doors," she suggested in her gravest tone. The screaming, which Y/N hadn't noticed had stopped, quickly resumed as the people vacated the streets with haste.

A crying child remained. Y/N knelt next to him, horror growing.

"Hey… was this… was this your mum?" She asked the inconsolable six-year-old. Gasping for breaths around his sobs, he nodded and wrung his shirt with his pudgy little hands. Sighing, she scooped him up. She couldn't leave him behind, but she had to find the Avengers and soon. "Do you know where your dad is?" she gently questioned.

"He-he-he's de-ead too-oo" the unfortunate child howled. Y/N flinched.

"Ok, you can come with me then," she decided, more to herself than to him. Using her enhanced strength, she raced down the street with him on her hip. More zombies were appearing, more people were dying, and some of them appeared to be coming back from the dead as she ran past. She didn't stop; there wasn't time for that. She had to find her friends. Maybe Tony could fix this problem from the roots.