A Story Needs A Plot

Pretty obvious right. We all learned that in school. Plot is an essential element to a story. In fact without a plot you don't really have a story, you have a scene.

So, why does it seem that I have a hard time coming up with a plot?

I'm great at scenarios and back story:

1) Girl finds out that the old word processor her grandmother gave her is magic and whatever she types happens.

.... yeah, but then what? What happens? What's the main conflict of the story and how will the girl overcome it.

2) A "good girl" and a "bad girl" end up being step-sisters. The "good girl" does something "bad" and the "bad girl" gets blamed.

.... okay, but what does she do? And what are the consequences for everyone involved?

3) Historical fiction based on family history of German immigrant family living on a farm and the daughter has to find a way to get to go to high school.

---- and then what?

Although not all stories have to follow the same pattern, it is helpful if the main gist of a story can be fit into the following sentence:

Main Character is a [description here]. His/her life changes when important thing happens. He/She must accomplish this task or the consequences will be something unpleasant.

So, how does When Mike Kissed Emma fit into that description?

Emma is quite happy with her life and boyfriend, she's not looking for changes. But then she gets cast opposite Biker Mike in the school play and discovers there's more to him than meets the eye. Emma must decide if it's Mike or Trevor she wants to be with, and is she willing to lose her friends if she follows her heart?

And how about Emily's Song (yet unpublished time-travel story)?

Emily's biggest problems are getting her report on the Battle of Bull Run done on time and getting Aidan to ask her to the prom, until she slips through a time portal and ends up at the beginning of the Civil War. Now Emily has to figure out a way back home before she is trapped forever. But would going home spell doom for her friend's son - not even born yet? And what about Sam, the soldier who captures her heart.

Or Reality Ali (a story currently being revised, so things are subject to change)?

Fourteen-year-old Ali has always wished that her movie-star mother would pay more attention to her. Now she's getting the chance to be in her mother's reality show. But Reality TV and reality have little in common and Ali needs to find a way to reconcile the two before she ruins all her friendships and her father sends her off to an all-girl Swiss boarding school.

So what kind of trouble do you give your main character? And what will happen if the problem isn't overcome?