Well, to answer that, we need to know more about the 'Impossible' you're referring to. Is it a film, a novel, or something else? If it's a work of fiction, chances are it's not a true story. But if it's a documentary or based on real people's experiences, then it could be.
It's not straightforward to determine. 'Impossible' could refer to events that are rare or unlikely in real life but not necessarily untrue. Or it could just be a fictional creation with no basis in reality at all.
Well, it might be a unique take within the series. Maybe it's about a mission that seems as impossible as dealing with a ghost, something very elusive and hard to grasp. It could introduce elements that are spooky or very difficult to overcome, like a mystery that's as hard to solve as proving the existence of a ghost.
An 'impossible real story' could be a story that seems too strange or unlikely to be true, but actually happened. For example, a person surviving a fall from a great height without any major injuries. It defies our normal expectations of what is possible in the real world.
Partly. While the main events and the overall situation are based on real incidents, some elements might have been fictionalized or dramatized for the sake of the story.