How many different stories can this lead-in lead to?
Premise: 3 sisters, 2 late teens/early 20's and 1 mid-teen. The older 2 sisters are outgoing, fun, friendly individuals with a very strong protective instinct toward their younger sister, Cally. Cally is extremely intelligent but almost cripplingly shy. She envies the older sisters their ease with people but also has trouble just interacting with immediate family. This has been the pattern of Cally's life growing up so far, and looks to be the same in the future but Cally has a secret...
Lead-in comments/questions: How is the rest of Cally's family & life structured? What exactly is Cally's secret? Does anyone else know of Cally's secret? Is Cally's secret mental, physical, personal, impersonal, safe, dangerous, humorous, sad? Does Cally's secret ever get exposed publicly and what would the reaction be? Does Cally's secret change her in any way (physically, mentally, emotionally, socially)? How does the over-protectiveness of Cally's older sisters play into the story? Does it help or hinder Cally?
I would like to see how many different storylines authors can produce out of this lead-in. I have seen other "challenges" produce a lot of interesting reading and am curious if there are authors that would pick up this challenge.