One, it's not only just one sentence per turn. You can write only one if you wish, but you will find you'll be writing a paragraph or maybe two per turn.
Second, it's a story that we want to go in a particular direction. We want the plot we start with to carry through until the end, and we want the story to actually /have/ an ending.
Three, you don't choose where it goes. You look at the options the previous player gave you and choose where it goes from there.
I'll start and you'll catch on.
I stared at the swinging doors of the bank in thought, fingering the pistol at my side. It wouldn't take long; this would be easy, if only I moved quickly. I waited until the last customer stepped out of the building, mounted his mare, and trotted off. I slid the black mask over my mouth and started for the bank, but hesitated. Should I really do this?
A. Yes.
B. No.
(thanks for the idea, Cor *applause*)
) 
