The story takes place on present-day Earth. Maybe give or take a few decades or centuries. However, the world is really young. It doesn't have billions of years behind it, nope, it has only been around for a few thousand years. In either case, what about all the scientific evidence that the world is much, much older? What about ancient fossils and radiometric dating? What about starlight that has traveled at light-speed from distant galaxies for billions of years, and so on? There are several approaches to this: Examples of Earth Is Young include: