Set in 1970’s Wyoming, childless couple Nancy and Ray Cooper return home one evening to find an abandoned baby boy on the doorstep of their remote ranch. Against his better judgement Ray agrees to keep the child, who looks to be around six months old, and they name him Samuel. But this is no ordinary baby. Nancy quickly develops a strong bond with the child and they slip easily into family life, but Ray soon starts to notice that he behaves differently with each of them. Samuel is less engaging and only smiles when Nancy is around. After a mysterious sequence of events, Ray voices his concerns about the baby to Nancy, suggesting that he is somehow responsible. Nancy dismisses the accusations believing that Ray is suffering under the stress of their sudden change in circumstances. Things begin to deteriorate between them and Ray struggles to understand what he is experiencing on a daily bases, but the more he tries to convince Nancy the more she defends Samuel. As the wedge between the couple grows, Ray's accusations become even more absurd. Only when Nancy begins to experience inexplicable events herself is she forced into the awful realisation that if what Ray says is true, then perhaps, there is something very unusual about Samuel.