I had never taken much notice of my sister-in-law. Emma had been overweight for as long as I'd known her, and the two children she had only added to her size. She was five years younger than my wife, and was twenty-one when I married her sister.

My wife, Jocelyn, is 5'4" tall, dark black hair and brown eyes, and weighs about 125. She has a perfect hourglass figure. She is wonderful in bed - at least she was, until we had the kids. Then she lost her interest in sex. We used to make love three or four times a week, or more. We stopped completely of course during her two pregnancies, but after the second baby was born, things never really got started again. The birth had given Jocelyn a lot of health problems, and she was a long time recovering. Somehow, four years later, our sex life was still not back on track, and I was starting to think this would be permanent.

By this time, my wife was 34 years old. She still had her figure; the only sign of the passage of time was a bit of grey that she had to dye out of her hair, and the usual wrinkles that go with age. But there was no question that she was still a babe. This made things all the more frustrating for me. Watching her change her clothes, or go in and out of the shower, or wear a bikini at the beach, was sheer torture for me. For some years I had been in a constant state of unsatisfied arousal. I was beating off so much I was risking carpel tunnel syndrome. But cheating on my wife had never crossed my mind.

One hot summer's day we went to the birthday party of one of my nieces. I hadn't seen my sister-in-law or her family in some time, since the previous Christmas. My wife had mentioned that her sister had been dieting, but this hadn't really registered. I was very surprised when I saw Emma. Instead of the very overweight woman I was accustomed to, I saw a younger, even prettier version of my wife. She had the same hourglass figure. Her ass looked simply incredible in the jeans she was wearing to show off her new body. She was rather shorter than my wife, barely over five feet. She looked so petite and gorgeous now, and I had trouble believing this was the same dumpy woman I had known for so long. She wore a loose top that left her midriff bare, and gave anyone who cared to look a generous view of her luscious breasts whenever she had to bend over (which was frequently, given that there were a lot of young children running about at the party who needed attending to). I found myself feeling guilty over the hard-on my sister-in-law was inspiring in me.

The party ended and we went home.

"Doesn't my sister look great?" my wife asked. I muttered something about her looking o.k., because my wife is a very jealous type, and I always had to be careful about what I said. But of course, Emma had looked great, and the next morning in the shower, it was to fantasies of fucking Emma that I masturbated myself to a very strong orgasm.

An entire year passed. At home, nothing had changed. My wife still was not interested in sex. I was still sexually frustrated. I had asked my wife to go to counselling together to see if we could somehow get things going between us, but she dismissed the idea out of hand, which made me very angry. But of course there was nothing I could do about it. I continued to have fantasies about her sister, but I knew that there was no way I could ever have sex with my sister-in-law. First of all, Emma would never go for it, and if she did and we were found out, the family would be torn apart. So I never gave it serious thought.

But all this changed. Whether it was my increasing horniness that was responsible, I'll never know, but it certainly could have been a factor. My wife's work took her out of town every now and again. She really looked forward to these business trips with her boss, leaving on a Friday afternoon, flying to some other city and returning the following Sunday night. I'm not stupid. For a while I had suspected she was having an affair with her boss, but I never had the slightest evidence, and it was only her lack of interest in sex that made me so suspicious. But perhaps she wasn't having an affair. It may be my resentment of our lack of sex life made me want to believe she was having an affair with her boss, so that I would feel justified in cheating on her. I don't know. But that is how I felt, and that is how things stood, when one Friday in November when my wife went off on another of her trips.

What made things a bit different this time was that other members of the family were also travelling. My wife's parents were vacationing at the time in England. They were returning to the homeland for a month to visit their old haunts. My sister-in-law's husband was also away, a hunting trip with his buddies. He'd been negotiating with his wife for months if not years to be allowed to go off with his friends, leaving Emma alone to take care of the two young children.

Friday night, I got a call from Emma.

"I'm at my parent's place. I brought the kids here for a change of scene, but I think it was a mistake. They're bouncing off the walls and I can't control them. Could you bring your kids over? Maybe they can keep each other occupied!"

I thought this was a great idea. My kids are also a handful, and I liked the idea of the two sets of kids amusing themselves instead of me having to do the job. So I agreed right away, and in no time we were off. My in-laws live only a few minutes away, so once I had packed pyjamas, books, toys and the kids' favourite stuffed animals, we were off.

Emma greeted me at the door, looking beautiful as she always did now. She was wearing her long black hair straight. Her tight ass was not in view this evening, as she was wearing some very baggy track pants that were probably a relic of heavier times. She was wearing a very unsexy sweatshirt, which nonetheless could not completely hide the fact that her breasts were very full, and that her nipples were erect from the cold. Her youngest child suffered from allergies that were aggravated if the furnace was turned on, and so she was trying to avoid turning on the heat if she could.

It was just past 5:30 when I arrived. The kids ran around like wild animals in the basement for the next 2 hours before we put them to bed. By 8:30, they were fast asleep, dead to the world.

"Well, what should we do now?" said Emma.

Needless to say, I didn't suggest the first thing that popped into my head. Instead, I said,

"How about a movie and pizza?"

"Great idea! You order the pizza, I'll pick the movie!"

That suited me fine. I went to the phone and I was making the order when the pizza order lady asked if I'd like anything to drink.

"Emma, what do you want to drink?" I called.

"Don't order anything to drink. There's pop and even some wine in the cold storage."

My in-laws had made a cold storage room in their semi-finished basement, and they usually kept all kinds of stuff in there. So I completed the pizza order. Emma was still puzzling over the movie to watch, checking the cable guide. There were lots of choices. So I figured I might as well go downstairs and get something to drink with the pizza.

It's funny how one little thing can change one's life forever. I mean, a lot had to happen in order to place my sister-in-law and me in the same house with no other adults around. That had never happened before, and probably never would again. The kids had gone to sleep easily, which was nice, and not that common. But the fact we were alone together would not, by itself, have led to a night of great sex made greater by its illicit nature. There was too much for each of us to lose. But one last piece of the puzzle fell into place when I went downstairs to the cold storage room.

I was just reaching for the wine when I notice a bottle of alcohol on the shelf. It was straight alcohol, with nothing added. My father-in-law liked to make his own Grand Marnier, and bought pure alcohol for the purpose. That his own concoction tasted like crap never deterred him. He would serve it after dinner and we would all have to pretend to love it. I'd heard how he made it. So I wasn't surprised to see one of the ingredients, raw alcohol, in the cold storage.

Now alcohol has no taste and has no odour. Of course one can tell when someone has been drinking, but the odour is not alcohol. It is some other substance that is in the drink along with the alcohol. I knew this from my work as a lawyer, defending drunk drivers. A toxicologist had told me this some years before.

In a flash there came to me not a mere thought, but a plan. No sooner had the plan come into my head than I acted on it instantly. I picked up the bottle of wine (which fortunately was white) and the alcohol. The wine was cheap and had a screw top instead of a cork. I opened it, and poured about a quarter of the bottle into the laundry tub. I opened the alcohol, and refilled the wine bottle with it, and then closed up the wine again. Then I made my way upstairs with the wine, which was in a 1 1/2 litre size (for any American reading this, that's about 1 1/2 quarts).

I put the wine in the freezer to wait until the pizza arrived, which was not long. We set everything up in the living room, on the table in front of the couch. With nightfall the house had gotten only colder, and Emma asked me to get a fire going in the fireplace, which I did, and by the time the pizza arrived, there was a warm blaze going. Emma got the pizza and returned to the room.

"So what are we watching?" I asked.

"A chick film, of course!"

I couldn't have cared less. I fetched the wine from the fridge, and returned with it and two glasses. The wine was German, and very sweet. Both Emma and my wife liked very sweet wine. I can't stand the stuff, myself. It's like drinking pop.

"Mmmmmm that's nice!" said Emma, taking the first of what I hoped would be many sips. I had a glass of wine before me, and I pretended to drink mine as we ate the pizza and watched this sappy move. Like most chick films, it was very, very dull. As usual for the genre, the film was about a family where people didn't get along at all, and the female lead was having man troubles. By the end of the movie, the family members had come to a better understanding of each other, and the female lead had bagged the male lead, so all was well.

But there were other developments during the movie. There was a large potted plant on a side table next to me, and I had been pouring my wine into it from time to time. Every now and again, I would pour myself some more, and occasionally, but not always, I would fill up Emma's glass.

"Are you trying to get me drunk?" she giggled at one point.

"I doubt you'll get drunk on this. Not much alcohol in this German stuff, and I'm drinking twice what you are" I said, filling her glass up again. But I noted that her voice was already quite slurred, and I knew she was well on her well to being drunk, if she wasn't there already. I remembered her wedding reception. She had had a fight with her father that day, and it had almost ruined the wedding for her. She drank far too much at the reception, and was almost out of control at the end.

By the end of the movie, there was no doubt in my mind. This girl was inebriated. Thus, when I suddenly pressed her back full length on to the couch, my lips on hers, my hands on her breasts, she was very befuddled and it was a moment before she started to resists.

She tried to mumble something about what was I doing, and I said she should keep her voice down so as not to wake the children. This silenced her, but by now she had awakened to her situation, and begin seriously to resist. She started bucking her legs, trying to throw me off her. But it was no contest. I am 6'2" and weigh over 200 pounds. I was over a foot taller than Emma, and I was easily twice her weight. She was not going to be winni ng any wrestling matches.