Since I haven't read the actual 'the vanishing girl short story', it's hard to say precisely. However, it could be a story that delves into the mystery of a girl disappearing. It might explore the emotions of those left behind, such as her family and friends. Maybe there are supernatural elements involved, like she vanishes into thin air, or it could be a more down - to - earth mystery with a human - caused reason for her to disappear, like she's running away from something or someone.
In the 'vanishing hitchhiker' short story, typically a driver picks up a hitchhiker. They might have a conversation during the ride. Then, at some point, usually when the driver reaches the hitchhiker's destination or stops for some reason, the hitchhiker mysteriously vanishes. It often leaves the driver bewildered and sometimes leads to further investigations or just becomes a spooky tale they can't forget.
The two main characters are usually the driver and the hitchhiker. The driver is the one who offers the ride and is often left perplexed by the vanishing of the hitchhiker.
It's not based on a true story. The plot and characters were invented by the writers for entertainment purposes. There are no real-life equivalents or incidents that inspired it.