The film focuses on eccentric Mame Dennis, whose madcap life is disrupted when her deceased brother’s son Patrick is entrusted to her care.

Distraught when her middle-aged lover breaks a date with her, 21-year-old Toni Simmons attempts suicide. Impressed by her action, her lover, dentist Julian Winston reconsiders marrying Toni, but he worries about her insistence on honesty. Having fabricated a wife and three children, Julian readily accepts when his devoted nurse, Stephanie, who has secretly loved Julian for years, offers to act as his wife and demand a divorce.

Felix Ungar has just broken up with his wife. Despondent, he goes to kill himself but is saved by his friend Oscar Madison. With nowhere else to go, Felix is urged by Oscar to move in with him, at least for a while. The only problem is that Felix is neat, tidy, and neurotic, whereas Oscar is slovenly and casual.

In this film based on a Neil Simon play, newlyweds Corie, a free spirit, and Paul Bratter, an uptight lawyer, share a sixth-floor apartment in Greenwich Village. Soon after their marriage, Corie tries to find a companion for mother, Ethel, who is now alone, and sets up Ethel with neighbor Victor. Inappropriate behavior on a double date causes conflict, and the young couple considers divorce.