Plot for short story

I've had a couple ideas for the plot of my short story, and i personally that they are all really cool.  In fact, i like the several plot ideas a lot that i can't decide as i would assume a lot of you guys have the same issue because our minds are so incredible that so many things are created its hard to choose.  I guess i could explain one of them so here it goes... Niko is out one night at a club on a pretty average Saturday night with his friends.  He's having a great time when he sees a immoral action done, the abuse of a women, having his own sense of morales he beats the man who struck the women.  Unknown to Niko however the man beating this women (while still incredibly uncool and sick.) Was a son of a major mobster, Lorenzo "Fabuloso" de peluche.  I don't know a good name yet so don't look at me like a complete idiot i know you will so quit it.  While Niko couldn't care less who this sick man was beating a women as you might have assumed with common sense this causes some problems for him and the plot goes on to explain the hardships of dealing with the mob and other things in the way that he has to deal with but thats pretty much the basis of my plot and it needs a lot of work but i think it will turn out to be really cool in the end... Can't say how excited i am to write my own story it seems really cool.