Fletcher Reed, a fast-talking, habitual liar, divorced father, is an incredibly successful lawyer who has built his career by lying. He is used to giving priority to his job and always breaking promises to be with his young son Max, but Fletcher often lets Max down, by missing his son's birthday party. But even then at 8:15 Max decides to make him an honest man as he wishes for a whole day where his father can't lie. When his son Max blows out the candles on his fifth birthday, he only has one wish - for his father to stop lying for 24 hours. When Max's wish comes true, Fletcher discovers that his mouth has suddenly become his biggest obstacle