William, a shell-shocked survivor of the disastrous battles of world war one, returns home to New Zealand and is granted a remote, marginal holding of land, under the soldiers settlement scheme. He takes his young family, who hardly know him after the years of war and they try to build a home in the wilderness. When they start finding their livestock killed and partly eaten, William begins to sense they have encroached on the territory of something dangerous. William begins to catch glimpses of a fearsome creature; a beast that shouldn't be there; that doesn't belong. Only William ever sees it, and even he never gets a good look. His skeptical wife tries to convince him he must be seeing wild dogs, but when the mutilated body of their farm hand is found, William and family trek back to town to get help. When he tells stories of a mysterious monster, it is presumed that William is mad from his war experiences and is suspected of the farm hand's murder. The authorities take William's family away from him and arrest him, but he escapes. Alone, William returns to his holding, knowing that the only way to prove his innocence and get back his family and his land is to take on the beast by himself.