John Gustafson (Jack Lemmon) and Max Goldman (Walter Matthau) are two curmudgeonly neighbors who have been at each other's throats for years. The rivalry of the former friends intensifies when Ariel (Ann-Margret) comes along and provides a love interest for both of them. When Max finds out that John is experiencing family troubles and financial ruin, however, he steps in to help. Their bond is further cemented when John has a health scare and Max makes the ultimate sacrifice for his friend.