This is really fucking long. If you are not willing to wait 5000 words for them to have sex, you should probably find another story. I considered putting it in two or three installments, but didn't want to. This way makes the most sense. I think my next story will be something more fun. Maybe I'll write another Little Sister sequel. Or not. We'll see.

Part One: Sister and Brother

My grandpa has always been, to put it one way, insane. He's brilliant, almost the stereotypical mad scientist. He worked on the atomic bomb that was dropped on Hiroshima. Since then, he has been terrified of nuclear war. He still thinks that the Russians are after us all and that we're all going to be bombed to hell within the next couple of years.

This is why he built the bomb shelter.

Before this story, I had never been in the bomb shelter. The bomb shelter contains four medium-sized rooms: a dining room/kitchen, a living room, a bedroom, and a “study room” from which one can monitor conditions thirty feet above, on Earth. There's also a small bathroom. I know the bomb shelter inside and out, because I spent the last three years of my life there.

My twin sister Felicia and I were seniors in high school, eighteen years old. We hated each others' guts. We were easily the two smartest kids in our class, and vying for the position of Valedictorian. Whoever got Valedictorian would get a free ride to any college. Whoever lost would get nothing.

Our parents had died in a car wreck years before, so we lived with him. We were used to Grandpa and his craziness. It was his craziness, though, that saved our lives.

Me and my sister were sitting together, watching TV when it happened. Grandpa was off giving a lecture to some poor group of scientists somewhere. I think I had The Office turned on.

“Emory, change the channel, the news is on,” said Felicia.

“Fuck you, I want to watch this,” I told her.

“Emory...” She was mad, but that didn't scare me. My sister is a very small woman, barely over five feet tall and with 32-22-34 measurements (I know this now. I know everything about my sister, and she knows everything about me.) She has a pale body, and C-cup breasts. I guess you could say that she looks a little like Katy Perry, but dresses much more modestly. Her face has a sort of haughty beauty. Her entire body seems to shun everyone. The way she walks, the way she speaks, even her face seems to convey the fact that she doesn't need anyone, that she is beautiful and cunning, and that she knows it. And she is, and she does.

She reached out crossly and tried to grab the remote from next to me. I snatched it away from her, stood up, and held it above my head. Being almost six feet tall, she was now incapable of reaching it. She screamed as she jumped up and down. Almost all of the time, my sister seemed intimidating and cold. But when she was put in a situation that she had no control over, she would become scared, angry, frightened. I now know this better than anyone.

Finally, she sat back down. “Fine,” she sniffed. “Let's watch your stupid show.” She resumed being haughty and cold, but for just a second. Suddenly, The Office snapped off and was replaced by that channel's local news anchor. He looked flustered.

“This just in from Washington,” he said, apparently having difficulty keeping a level voice. “We have just received reports that the American stockpile of nuclear weapons has been raided by a militant group who apparently are referring to themselves as 'the Order of Jehovah' some four months ago. At latest report, we have reason to believe that they have found means to smuggle over three hundred nuclear weapons across the world. Two minutes ago this organization released an ultimatum; that they will destroy every living thing on Earth if all world leaders do not issue a statement of repentance-”

I still don't know everything about 'the Order of Jehovah.' From what I had heard, they are a religious fundamentalist group who sought to bring about Armageddon by killing everyone everywhere. I never got to find out any more, though, because the television suddenly faded to static. Felicia looked at me. She no longer looked calm, cool, or haughty. She looked terrified. “What do we do?” she asked.

I whipped out my cell phone and speed dialed Grandpa. This seemed like the kind of moment his craziness might be useful. As the phone rang Felicia flipped through the channels, searching for anything that still came in.

“Static... static... static...” she said, sounding terrified. “Static... static... Fox News... static... static... damn it, why isn't anything on here?” Finally, she hit a channel that was still broadcasting.

“New York destroyed,” the anchor was saying. “Nuclear radiation and fallout is dispersing with the wind to the northeast. Reports of over thirty bombings worldwide, estimates of billions dead...”

Grandpa picked up. “Emory, is that you?”

“Grandpa?”

“All right, listen close,” he said, skipping the greeting. “I need you to listen to everything that I say. I need you and your sister to go to the closet in the basement immediately. In there is a phone. I need you to dial 1-8-7 and then just wait.”

“What? Grandpa?”

“Just do it!” The call ended.

Felicia was shaking all over. She was staring at the TV screen, which had once again turned to static. “Felicia, we have to go to the basement,” I said.

“I... don't... want... to... go.”

“We're going.”

“No.”

Sighing, I picked up her tiny body and began carrying her down the stairs. She struggled, pressing her little butt against me and trying to squirm out. It didn't do any good. As we were about halfway down the stairs, there was a tremor, like an earthquake. We were flung the rest of the way down, landing with a smack on the carpeted floor. Debris fell around us. When it was over, I stood up. Everything seemed fine. I grabbed my sister, who seemed to be in shock, and carried her the rest of the way to the closet. I entered it, pulled her in, and pressed the three numbers on the phone. As I did so, there was an enormous blast. I felt the house collapsing on top of us. But then, the closet began disappearing into the ground, like an elevator... I saw cables around us as we went further and further. The noise from above us died down first a little, then completely... and then the elevator stopped. There was a ding and a door opened.

“Where... where are we?” asked Felicia.

I looked around, staring into the darkness. I couldn't see anything. “Hell?” I guessed.

Part Two: Ends and Beginnings

I stood up and walked forward. My right leg was in great pain, but I didn't think it was broken. As I took the first step forward, dozens of lights switched on. In front of me was a room that looked like it had been taken right out of a history textbook. It was a sizable living room. On one end was an enormous television with a tiny screen, which looked like it was at least fifty years old. Surrounding it were wooden bookshelves filled with old books, although most of them looked like they were in excellent condition. A couch and an old rocking chair were seated in front of the television. An exercise bike, a treadmill and a weight set were sitting in the corner.

“Did we fall into a time machine?” I asked, incredulous.

My sister moaned from behind me. I turned, having forgotten all about her. She was still lying on the elevator floor. Her face looked like it had been scraped but overall she looked fine. I reached out my hand and pulled her up. Her clothes were incredibly ripped and torn. As she stood up, the shirt simply fell off of her body, onto the floor, revealing her thin, pale upper body. She was scratched in a few places, but not too bad. But with her half naked, and her long wavy black hair falling messily over her eyes and face, her wounds weren't what I was thinking about at the moment.

“Oh,” she said softly. “That was my favorite shirt.”

“Let's see what we've got here,” I told her. Next to the living room was the kitchen. I opened all of the drawers. There were hundreds of cans of soup and vegetables. An industrial-sized freezer filled with meat and bread was next to it. There were cans of dried fruit. There was an oven, but no microwave. In one drawer we found ten bottles of whiskey. In another was a single handgun. Only one drawer, a big one, was locked.

On the other side of the living room was a bedroom. Inside was a single full-sized bed and a closet. Within the closet was a lot of clothes: all of them looking like they were from the 1950's. There were suits, ties, button-down shirts, pants, housewife dresses, blouses, poodle skirts. Absent were T-shirts, jeans, or anything that revealed the body below the neck. Next to the bedroom was a bathroom, complete with toilet, shower, and the washer and dryer.

There was a final door, this one emerging from the kitchen. Behind it was the largest room yet. It appeared to be some sort of scientific laboratory. Inside were all sorts of monitors and readouts and things.

“Do you understand any of this?” I asked Felicia.

“No,” she said. She was still topless. I was still staring at her. Bad thoughts were going through my mind. The human race might be wiped out, and I was just thinking of how if me and my sister were the last people... or even some of the last people... wasn't it our duty to...? It would be a pleasant duty.

No... I couldn't be thinking things like that.

A screen suddenly flipped on in front of us. My grandpa's face, much younger, appeared.

“Hello,” he said. “Welcome to my bomb shelter. I had this constructed earlier this year, 1948, because I knew those Russians were going to come after us sometime. And if this message is playing, they have. Nuclear bombs have been dropped.

“I can only hope that I am with you, but I know I won't live forever. So if I'm not: The elevator will not operate until my equipment indicates that the planet's surface is once again suitable for habitation. In the event of a major nuclear strike, this may not be for months, or even years. Everything necessary for survival is here: food, water, clothing, everything. I want you to do your country proud. Be fruitful and multiply. You may be the last humans left in America, or even the last humans left on Earth.” The screen disappeared.

I didn't know what to say. Everything I had known, everything I had ever known, was gone. Felicia started crying and so did I. We held each other, and cried, and thought about everything we lost. The thing was, you couldn't think about it in terms of “everything is gone.” That didn't make any sense. I had to break it into pieces. Grandpa is gone. My school is gone. All of my friends are gone. My future, my dreams, my hopes, all gone. Everyone else's future and dreams and hopes were even more gone than mine. Me and Felicia cried together for hours.

I gained control of myself first.

“We're going to beat this, Felicia. We're going to beat this.” I wiped my face off. “Listen, go and shower off and put on some different clothes. I'll get supper going.” She nodded silently and rushed off.

I started to prepare a ham and some canned peaches. Fifteen minutes after my sister had gone, she re-entered the room.

The change was stunning. She was wearing one of the housewife dresses and had her hair back in a bun. The haughty, in-charge look had returned to her face. She looked absolutely stunning. I wanted her so badly all of a sudden. She might be the last woman on Earth, so was that wrong? Did the concepts of right and wrong exist anymore? I shook my head. I would have to take this one day at a time.

“Come on, you don't know anything about cooking,” she said, pushing me aside. “You're going to burn this thing. Go fill up this jar with water.”

I gulped, nodding. One day at a time.

Part Three: Adam and Eve

The only things we could do for pleasure in the bomb shelter were read and exercise. We did plenty of both. I spent two hours a day on the exercise bike and an hour on the weights. I had read eight books by the end of the first week. They were mostly old books. The newest one we could find was To Kill A Mockingbird, apparently published in 1960.

We also discovered, based on a journal we found in the laboratory, that the last time anyone had been down here was in October, 1962.

“The Cuban Missile Crisis,” pointed out Felicia.

“Grandma divorced Grandpa right after that,” I remembered. “I wonder if that's why.”

“Well, if someone dragged me into this place for a long time for what ended up being no reason, I'd be pretty mad, too,” she said. She was wearing another of the fifties dresses. I had on a white button-down shirt, plaid pants, and a tie. We had music in the background. Grandpa had dozens of records down here, none more recent than Buddy Holly. I was relaxing in the rocking chair, she was lounging on the couch. I was drinking Jack and Coke. In this living room, we looked like a Norman Rockwell painting gone wrong.

“Just think,” I told Felicia. “If all of this hadn't happened, we'd be graduating right now. We'd be on our way to college.”

“So what?” asked Felicia. “We're not.” She had been saying things like this lately. She seemed to refuse the possibility that we could have ended up anywhere but a hundred feet underground.

“But think about it,” I told her. “I spent all of high school studying and doing every extracurricular I had time for, just to get into a good college. Just to beat you. I tried so hard that I never even had a chance to get a girlfriend, or even make any really close friends. And what was the point? Just so I could end up down here.” I took another sip of my drink. I never drank before I came down here. Then, a couple nights ago, I had been feeling particularly stressed, and decided to open one of the whiskey bottles. It was half gone now.

“I don't know what the point is, but you're sure not making anything better by whining about it. It's past midnight, I'm going to get some sleep. I get the bed tonight.” We had been trading off every other night who got the full-sized bed.

“Fine,” I said. “'Night, Felicia.”

“Goodnight, Emory.” She stood up and went to the bedroom. As soon as she left, I crept into my grandpa's laboratory. There, on one screen, was a screen with six videos on it. Each video was from the point of a camera in a different room in the house. There was the living room, kitchen, bathroom, laboratory, and elevator, but it was the bedroom I was interested. Because in there, my twin sister was undressing.

I knew how sick and wrong it must be, but I couldn't help myself. There was no porn here, the television didn't work. And my sister, well- she really was beautiful. I watched as she unbuttoned her dress from the back and started to pull it down. I grabbed my dick from beneath my plaid pants and began beating off. She stood there in just her underwear, her blue bra and panties showing a stark contrast from her pale body. Her dark mane of hair fell down her back but her bangs obscured her eyes. She removed the bra, and I saw her amazing breasts and dark nipples, firm and erect. She then pulled off her panties, showcasing her incredible butt and shaved pussy. I continued jacking off as she laid down in bed. I used to hate my sister, but in the last few days, I had come to love her. I had learned her toughness was just an act, had seen how human she really was. I wanted to be her lover. We could be like Adam and Eve, start the human race over again, make it better. We were, after all, both intelligent... both physically fit...

But every time I only thought these horrible thoughts while beating off. As I watched her climb naked into bed, I wanted her to be mine, my wife. I would give anything to ram my penis inside her, ejaculate inside her. I wanted my petite little sister. I wanted everything from her beautiful green eyes to her round, tight ass to her long, stunning legs. But as soon as I cummed (which I did now, all over the chair and my plaid pants) I would start thinking how horrible these thoughts were. I could never be in love with her. Even if we were the last two people on Earth, she was my sister. And she would never have me.

I wiped myself off, and using my pocketknife, I marked a tally on the wall of the lab, as I did every day. There were eleven little marks on the wall. How many more would there be? How much longer could I go?

I left then, so I wasn't looking...