Story Plot Generator is designed to help creative writers come up with story ideas by providing genre-appropriate locations, plot complications, details, and a main character.
The prompt suggests writing a story about a character who has assumed someone else's identity and is traveling on a colony ship toward a new home. Humans on this colony ship spend a large percentage of their day inside a virtual reality program. Our character's access to essential resources is dwindling.
If you don't like one or more elements of this random story plot, you can tap on the green bar above that element to have the program generate another, while leaving the rest alone. You can also tap the "refresh" button at the top to get a completely new plot idea.
You'll notice the bottom button, which will email you the information displayed on this screen, to make it easier to write a story from the prompt.
According to the developers, Story Plot Generator can create up to a million randomly generated story plots for you to use. I've not tested that theory out, but I have noticed that it seems to offer quite a few options.
The app is currently available free of charge from the Google Play store so there's no real risk in checking it out for yourself on your Android tablet or phone.
I've usually been able to come up with story ideas on my own without much trouble, so I'm not sure how much value this app will have for me. Where I think it could be useful is in generating ideas for fiction writing practice, where I might be trying to practice story openings, plotting, or some other aspect of fiction writing. I'd use the app to generate a random situation and then try to come up with a good opening or plot outline for the story.
Below are a few more screenshots of story ideas to give you a more complete picture of what the app can do.