How to come up with Plot Ideas

So you've read the article on how to write a script. But now your thinking, how do i get to the point of writing a script when i can barely come up with a plot. Well it actually is something really easy. Creating a plot for theatre/film is just like creating a plot for a book. So what you would do, is come up with a one sentence plot. Something simple, that gives you a base to work off of. Now from that, i would create the characters. this way, i can have a really good base to work off of when i create the final plot. So after i've done that, i will think of different directions i can take the plot. There are always multiple choices and the two most obvious ones are happy ending/sad ending. Time and time again, i will watch a short film where the plot wasn't worked out enough, and the story line leaves you hanging in a bad spot. If you are going to leave the audience hanging, you want to make sure that it is a good spot to leave. Now since some of you might still need help, here's what i'm going to do. I am going to give you a one liner, and in the comments post a plot that you think would be good for the one liner, and i am going to tell you what's good and whats bad. Here is your one liner:

A Child is lost in the city without anyone or anything to help them.

So post your full plot beneath the article and ill get back to you on advice.