The story takes place in England in 1921, and the defeat in World War I enveloped the whole country with a repressed and painful atmosphere. Florence (Rebecca Hall Rebecca Hall) is an anti-counterfeiting righteous, she has a strong sense of justice to expose lies to expose the truth as her duty, she does not believe that there are ghosts in the world, there are only sinister hearts. In a boys' boarding school, there are rumors of being haunted. In people's mouth, the ghost of an unnaturally dead boy lingers around the campus all day and refuses to leave. In order to allay the fears of students and parents, the school commissioned Florence to investigate. Florence soon began to work, and under her shrewdness, the truth of the incident gradually came to light. And just when she thought the problem had been solved and was ready to leave, an event happened that was enough to subvert all her beliefs in this life.