A soldier, Dan Stevens (Downton Abbey) introduces himself to the Peterson family, claiming to be a close friend of their son who died in action overseas. After the young man is welcomed into their very normal, Midwest home life, he insinuates himself further by befriending the younger son who is bullied at school, the parents, who both have their own personal problems and agendas and their older daughter, who has graduated high school, and is putting herself through school while working as a waitress. Then a series of accidental or purposeful deaths seem to be connected to the lives of this family, and to his very presence. This guest is not all that he seems, not even close.