Beth, a popular writer, and her husband Don, a well-liked teacher, share the kind of relationship that truly, seriously, for the love of God cannot be real: that is, they're actually in love. Even after decades of marriage, parenting, and successful careers, their physical spark has somehow not diminished; in fact, they seem to relish the opportunity to share a single ice cream cone and drive others including their son, Charlie, mad. But when Beth discovers that Don has been untruthful to her about his opinion of her work for years, Beth's world comes crashing down. Has their whole relationship been one Big Fat Lie?