James Upperton stays in pension Kirkby-Malhouse in Gaster Fell in Yorkshire waiting his cottage to be built on the moor. There, he meets a beautiful French woman, Miss Eva Cameron, which warns him about the danger of living in such an isolated place. A few days later, his cottage is finished and he settles. He receives a quick visit from a neighbor nicknamed "The Surgeon of Gaster Fell" which leaves him with a dubious feeling. Then a few days later Upperton decides to visit him. Not far from his house, he sees his neighbor beating a poor old man. He decides to learn more and, without being seen, he throws an eye in the house. He sees a cage where the poor man is held prisoner. A few days later, the same old man escapes and tries to enter in Upperton's cotttage, but he is catched up by the surgeon. All these strange events are explained in a letter Upperton receives shortly after. It is written by his curious neighbor,who is none other than the brother of Eva Cameron. He explains that his old father is suffering from insanity and he tries by any means to avoid him to be interned in a psychiatric hospital.