With the murder of Frank Larned (Hogan), his sister Martha (Bow) and her little brother were left unprotected and the object of unwelcome attentions from Jim Howard (Mason) and his half-witted brother. Roy Chambers (Austin), who was gassed in France during World War I, is ordered by the doctor to go to the mountains. Chance brings him with a police dog he has picked up to the Larned home. He finds that Martha is the sister of his buddy in France, who saved his life, and Thunder being the dog that came to his rescue. Learning the situation, he decides to stay awhile. Joe gets hurt and Roy rides for a doctor. Ez (Phillips), the half-witted chap, shoots him. Martha sends Thunder to find him, Jim comes and tries to get into the Larned home. Ez kills him and then attacks Martha. Thunder comes to her rescue. Martha and Roy then journey to the preacher together.