In Their Sleep is a French horror/thriller film. The film centers around a family who have just moved into a home in the country. Sarah's son, college student Loic, dislikes the isolation of their new home. A tragedy occurs and Loic is killed. A year later Sarah is alone in the home and on her way home from work late at night. As she is heading home a young man, same age as Loic, flags her down for help. A murderous burglar is after him. Sarah picks up the young man but soon finds that things are not what they seem.