Mr. Kent takes a taxi from the train station to his old home village of Agan after an absence of several years, intending to stay for a two-month holiday. The taxi driver and he encounter the ghost of Mr. Wainwright on the side of the road, a local curiosity and source of much talk and speculation. After walking through a gate without opening it, the ghost greets Kent as if they had only a few days ago had been socializing, though Kent hasn't seen Mr. Wainwright since he left his hometown many years before, and even then he never knew Kent's name. The ghost also is very pleased that Kent hasn't left the Hotel yet, as he had heard he left on the 17th of August. After the ghost begins to wander back to his deserted house, the driver explains to Kent that the ghost doesn't even suspect that he's not living and even when he was alive Mr. Wainwright had the uncanny ability to recall events in the future as if they were in the past, and many of the townsfolk rely on his predictions to catch early gossip and prepare for future events. So even though it's only the 8th of July, the driver says everyone in town already knows Mr. Kent will leave town on the 17th of August due to the ghost's ramblings. Continuing on their trip to the hotel, at Kent's request the driver begins to relate all the events leading up to Wainwright's murder by his housekeeper, Mrs. Carmody five years previously.
Mrs. Carmody's sister-in-law was Wainwright's housekeeper until she died and requested in her will that Mrs. Carmody take over. She immediately sees this as an opportunity to finally find security after years of strife and near-poverty. Once she takes over all the household duties, she will have almost unlimited access to Wainwright's finances. So she and her children (Bill and Pearl) prepares to move into Wainwright's house along with his granddaughter Phyllis. When she is driven to his house by this same taxi driver, they witness Mr. Wainwright's habit of walking through a solid gate. (The driver informs Kent that Wainwright did these things even when he was alive.) Though unnerved, Mrs. Carmody still remains set on her schemes. Strangely, when she first meets Wainwright, he acts as if she's simply come back after a short trip to town and asks if they can have dinner early. She thinks she is being ridiculed, but the driver explains to her that he's been talking about her for months, as if she had already been working for him, and that it's best not to upset him by asking questions. He also claims to have seen her sister recently, coming out of a courthouse, and that she looked a lot like her. The driver had previously told her of Wainwright's tendency to call people he sees in visions siblings of those he saw. So Mrs. Carmody knows that somehow at some time she will have a court case on her hands.
The driver concludes recounting these details to Kent as he drops him off at the hotel. The next morning Kent meets the ghost right outside the hotel, and they have a short conversation. The ghost is complaining that Mrs. Carmody is pestering him about the details of her "sister's" court case. Wainwright is confused by the fact that in all his life he has met many twins, and yet none of them seem to have contact with their siblings. The ghost soon after leaves, and Kent intends to follow him, but is drawn into a conversation with the hotel's manager. The manager relates the rest of the events preceding Wainwright's murder.
Mrs. Carmody is in town one day doing the grocery shopping when, to settle her anxiety on the matter, she enters the bank where Wainwright keeps his account, and she establishes to her satisfaction that she will be executrix of his estate until his granddaughter Phyllis comes of age. However, she would have to visit the courthouse to settle it all. She realizes with alarm that this is the moment when he saw her exit the courthouse. When she returns to the house, she hears Mr. Wainwright reminiscing about the time when his granddaughter and a neighbor's son got married. This is obviously one of his prophecies, as Phyllis is not even involved with anyone. If it comes true, Mrs. Carmody's dreams of running the estate and finances of Wainwright after his death are ruined. So she makes a plan with her son, that one night when everyone is absent from the house, he is to go in and rape Phyllis, forcing a shotgun wedding and thus keeping the estate in the family. Around the same time, Mr. Wainwright informs Mrs. Carmody that he is quite distraught over her sister's recent hanging, and praises her for having nothing to do with such a horrible person.
The hotel manager halts his story as he deals with a customer. Kent is now determined to solve the mystery of Mr. Wainwright. He purchases a small library of books on the supernatural, and in particular is struck by the works of J.W. Dunne on the subject of time. He becomes convinced that Mr. Wainwright is part of some sort of temporal anomaly. Determined to confirm his theories, he waits for an opportunity to meet the ghost. When they do, Wainwright acts as if it's the first time they've ever met. They chat and stroll back to the house. The ghost disappears, and Kent breaks into the abandoned house to look around. The next day he meets up with the ghost again as they stroll back to the house. Kent, to confirm part of his theory, asks Wainwright if the house looks a bit run down. Wainwright admits that it does, and is comforted that someone else sees it too. As they get closer, Kent continues affirming that Wainwright sees the ruined old house as it truly is. Although the ruined appearance usually vanishes as soon as he passes through the gate, this time the ghost continues seeing a ruined boarded-up house. He becomes terribly distraught, and vanishes soon after stepping up onto the porch. His theory confirmed, Kent dashes back to the hotel and asks for his belongings to be brought down immediately. It is August 17th, and the hotel staff had already packed everything up in accordance with Wainwright's prediction.
Kent rushes to a nearby town, where Mrs. Carmody is held in an asylum. He demands to speak with someone in charge, and explains that he must see her before it's too late. He speaks with the head doctor and explains his theory that Mr. Wainwright never was a ghost; that throughout his old age, he would momentarily walk into the future where he would witness and experience things, and return to his native time where his senile mind would relate his confusing experiences as memories of the past. Kent asks the doctor about the events immediately preceding Wainwright's murder by Mrs. Carmody. The doctor replies that late in the night when Carmody's son was to do the evil deed, that Mrs. Carmody returned only to find a note in her son's room saying that he has not carried out the plan, but that he has left for the big city. This enraged her, as she remembers Wainwright saying something about what a pity it was that he moved to the city. She suddenly interpreted everything Wainwright said and did as a very subtle and clever attempt to "rob" her of her inheritance. In her rage, she confronted him on the porch one evening as he returned from a walk, only to find him choked to death. However, it was assume she killed the man, and she was put away as criminally insane. Kent explains to the doctor that Wainwright choked to death on his own saliva, as the elderly as prone to due under extreme upset and trauma; and that he was in such a state because Kent had just revealed to him the true state of his house in the future. They rush into Mrs. Carmody's room, where Kent explains that he now has solid proof that she did not kill Wainwright, hoping that proof of her innocence will be sufficient to prevent her from suicide. As they leave, however, Kent realizes he's made a terrible mistake. Mrs. Carmody was always seeking security, and she had found it ultimately in the asylum. Now, her innocence proven, that security has been taken from her. They return to her room to find Mrs. Carmody's corpse hanging from a light fixture, her dress cut to ribbons and made into a rope.