Forbidden Fruit (Sister In Law)

Hey guess what!” she said excitedly. “My sister is going to be coming here for college!” Oh great I thought, can’t wait to have to deal with your little sister coming over all the time. She was 18 years old and from what I could remember, had a shitty entitled attitude. She was the youngest of the 3 daughters and was by far the most spoiled. “Oh.. that's great!” I responded, doing my best to hide my annoyance. I had gone to college in their hometown that was 4 hours away from where I lived, and had met Kate there. We began dating my junior year in college and had gotten married a year after we graduated. After graduation we moved back to my hometown. Her sister Ali was a Junior in High School when we graduated and I was sure she would be staying in their hometown for college. She was very attached to her mom and besides Kate, had no family on the other side of the mountain where we lived. Ali was a volleyball player and was built like one. She had long legs and a great butt. Kate had a great butt too but Ali’s was bigger. Kate is 5”2 with large double D boobs and a perky butt with brown hair. Ali was 5”9 with small tits, maybe Bs, but a donk in the back and blonde. Besides them having the same nose, you wouldn't know that they were sisters. Fast forward a few months and Ali was now in college, living in the dorms just 10 minutes away from our house. At first we didn't see her much. She was completely free in a new city and was enjoying her new privileges. We had lunch a few times over the weekends and she was much more mature now. Not nearly as annoying as I remembered her when she was in high school. Still, I thought of her as nothing but my wifes little sister. I had obviously noticed her big butt before but honestly hadn’t thought much of it. “Hey Mike, what do you think about grilling some steaks tonight. We can have Ali over and maybe watch a movie later? She said she was getting a little homesick to me and I invited her to spend the night”. I didn't think much of it. “Sure, that sounds fine.” I responded.