The 'the open door ghost story' could be about a haunted place where an open door is a key element. It might tell of a tragic event that occurred near that door in the past, and now the ghost of the victim lingers. For example, a person who was wrongly killed near an open door might come back as a ghost, and people passing by the open door experience cold spots, eerie feelings, or even see apparitions of the deceased.
I'm not sure specifically as there could be many open door ghost stories. Generally, it might involve a ghost associated with an open door, perhaps something spooky happening when a door is left open at night, like seeing a strange figure or hearing unexplained noises.
Well, in a 'the open door ghost story', it could center around the idea that the open door is a portal of some sort. Maybe it's a connection between our world and the spirit world. Ghosts might use this open door to cross over and interact with the living. It could be that the story involves a family who moves into a new house with a strange open door that always seems to be ajar no matter how many times they close it, and soon they start to notice strange occurrences like objects moving on their own or hearing whispers when they pass by the open door.