Warning: Major SPOILERS for Ghost Stories ahead
Jeremy Dyson and Andy Nyman's chilling horror film Ghost Stories may seem like a straightforward anthology held together by a skeptic's hunt for the truth, but the ending reveals something even more terrifying lurking under the surface. The film stars Nyman himself as Phillip Goodman, the host of a TV show dedicated to debunking the supernatural, who receives a letter from his hero, Charles Cameron. Cameron, who mysteriously went missing, tells Goodman that he's had a change of heart after encountering three cases that he couldn't solve, and challenges Goodman to try and explain the cases himself.
The cases are, respectively: Tony Matthews, a night watchman at a derelict former asylum, experienced a series of spooky happenings that culminated in a ghost sighting; Simon Rifkind, a nervous and highly-strung young man, ran over a monstrous goat creature while illegally driving his dad's car; and Mike Priddle, a wealthy businessman, encountered a nasty poltergeist that heralded the death of his wife and the birth of a monstrous child called Barty. But it's only after all of these stories have been told that things get really weird.
After hearing each of the stories - and witnessing Mike Priddle's abrupt and shocking suicide - Goodman returns to Cameron, enraged, and tells him that none of the cases prove anything about the supernatural, and that they're merely manifestations of the storytellers' troubled minds. At this point, Cameron rips off his face to reveal Mike Priddle's face underneath, and then for good measure he reveals that the wall of his caravan is just a painted backdrop. He steps through the backdrop and invites Goodman to join him, telling him that it'll just be the four of them - "You, me, Barty... and you-know-who."
The identity of the mysterious fourth party - a figure in a hooded coat who has been dogging Goodman's footsteps - is finally revealed after Goodman follows Priddle into a wooded area, and experiences a flashback to a terrible incident in his youth. The young Goodman is accosted by two bullies who make him stand next to a tunnel while they throw stones at him, but are interrupted by the arrival of another classmate - Desi Callahan, a mentally-disabled boy with a crudely shaved head whom the bullies mockingly call "Kojak." One of the bullies tells Callahan that he can be in their gang if he goes into the tunnel, where ten numbers have been chalked onto the walls, and memorizes the tenth number. Of course, it's just a cruel prank; there are only nine numbers in the tunnel.
Goodman starts to tell Callahan this, but is threatened into silence. Callahan goes into the tunnel, reading off the numbers, but gradually growing more panicked as the tunnel becomes narrower and narrower. Eventually he succumbs to an asthma attack and the bullies run away, with Goodman following them shortly afterwards. Priddle then returns and confronts Goodman about the fact that he didn't go into the tunnel to help Callahan, or run and get help, or even tell anyone what had happened to the boy. But the twists don't stop there.
In the final scene of Ghost Stories, the rotted corpse of Callahan accosts Goodman and forces his finger into his mouth as Goodman cries out, "Not again!" It's then revealed that Callahan's finger is actually a breathing tube, and Goodman is in a coma following a suicide attempt, lying in a hospital with little to no hope of ever waking up again. Everything he experienced throughout the rest of the movie was simply a manifestation of his guilt, fleshed out with details from his immediate surroundings. Mike Priddle is actually a senior doctor, Simon Rifkind a junior doctor, and Tony Matthews a hospital janitor. While the ending is certainly a dramatic twist, there are plenty of hints along the way that something isn't quite right.