Mortal Thoughts is a low-key thriller revolving around the relationship between two best friends who are involved in the death of one of their husbands. The movie unfolds as the events leading to a confession are shown in flashback. Joyce (Glenne Headly) is married to the abusive, unfaithful James (Bruce Willis). During an outing at a carnival, James is killed, and Joyce and her best friend Cynthia (Demi Moore) try to cover up the murder.