Plot

When famed paranormal psychologist Dr. Nandor Fodor investigates a family's claim of a talking animal, he uncovers a mysterious web of hidden motives. Soon, everyone becomes a suspect in his relentless pursuit of the truth.

In 1935, Hungarian-American para-psychologist Nandor Fodor began his investigation of a strange occurrence on the Isle of Man. An average British family, the Irvings, claimed to have been contacted by a mysterious entity at their farm: a talking mongoose named Gef (Pronounced "Jeff".)

Renowned parapsychologist Nandor Fodor travels to Isle of Man with his assistant Anne to investigate the case of Gef the talking mongoose, believed to live at or around the farmstead of James Irving, local wealthy merchant. The mongoose has been reported by several people to be heard speaking to them, prophesying about future events, reciting poems, and even making telephone calls; although one report of hearing Gef's voice took place in the presence of Irving's daughter Voirrey, who is known to be a skilled ventriloquist. Most of the local residents believe firmly in Gef's actual existence, although sightings of the mongoose are much rarer than ear-witness reports, and those are invariably cursory glimpses of some furry creature "out of the corner of the eye" for a split second.

Fodor becomes increasingly sceptical, especially after Irving's farmhand Errol says in conversation with him that "there's no Gef". Late at night, Fodor receives a phone call from Gef, who repeats to him the last words Fodor's father told him when he was leaving Hungary ("I shall never see you again"), and then announces that he will make an appearance for Fodor tomorrow. At a viewing organised the next day by Irving in his barn, a tuft of brownish fur is seen briefly under a wooden box. Fodor accuses Errol of complicity in perpetuation of deception by the Irvings, Errol retorts that "everybody wants to be happy" and perhaps Fodor would be happy if he "let people believe what they want to believe." Later in the evening Fodor gets drunk and forces his way violently into the barn where Gef made his appearance; Errol knocks him on the head with an iron bar and he comes to in a cell at the police station. Fodor's demand to be allowed to make a phone call to arrange his release is left unheeded, and he hears Gef's sneering and taunting voice. Fodor demands to know how Gef has come to know his father's last words to him, and Gef replies, "What if there is nothing after this, no Heaven, no Hell, just nothing? No awareness of the fact that we were ever aware at all?" Fodor then begs Gef to prove that he is real, or at least to scratch his outstretched hand on the wrist with claws - Gef's "little scratch" leaves three deep and painful gashes across his wrist; he bursts into tears and thanks Gef. On their way to London, Anne asks Fodor at least to accept the possibility of Gef's existence.

In London, Fodor renounces drinking, announces his intention to write an article about Gef and events on the Irvings' farm which will be truthful, yet without undue harshness - Gef's words have imbued him with everybody's needing to be remembered. He is seen at his father's grave coming to terms with differences between them in the past and unpleasant manner of their parting.

Photos from the 1936 book The Haunting of Cashen's Gap: A Modern "Miracle" Investigated by Harry Price and Richard S. Lambert are shown alongside the closing credits, followed by onscreen caption "Producers, cast, and crew wish to thank members (and mongooses) of Gef's army. However there is one person that we would not like to thank..." with logo of Legion M. The film ends with "a special message from the cast" as a post-credits scene in which all major performers (Connell, Downie, Beadle, Kaye, Lloyd, Pegg) join in bashing the film's director Adam Sigal, and with the final caption "Adam, in all seriousness... you suck". (thanks to Wikipedia)