Since I don't know the exact 'the cask full story', it could be a variety of things. It could be a historical account of a cask that played an important role in a particular event. Perhaps it was used to store supplies during a war or a long journey. Or it could be a fictional story where the cask has some sort of magical or mysterious property. Maybe it holds a secret that the characters in the story are trying to uncover, and the whole plot revolves around this pursuit of the secret within the cask.
I'm not sure specifically which 'the cask full story' you're referring to. It could be about a cask full of something like wine or other liquids. Maybe it involves a mystery or adventure related to this cask.