Robert (Jack Lemmon) and Nina Tracy (Judy Holliday) were once a happy couple, but eight years of marriage has taken a toll on their relationship. They decide to call it quits and get a divorce. In their ensuing freedom, they are excited to dive back into the world of dating. Nina has a date with a suave actor (Donald Curtis), and Robert meets a blonde bombshell (Kim Novak). However, when their dalliances get complicated, they quickly realize that single life might not be what they bargained for.