Helen Campbell is the eldest and most practical of three sisters, daughters of hard-working Irish emigrants living in New York City in the 1950s. She does what she can to keep the wild-child middle sister, Carolyn, in line and support the youngest, Peggy, as she pursues her dreams of becoming a doctor. Then Helen meets Charlie.

While it's love at first sight for those two, Carolyn's antics threaten to derail all the sisters' future happiness. However, through thick and thin, the three sisters strive to prevail, though not necessarily in the ways they thought they wanted.