Noah, a happily married New York City schoolteacher and novelist, and Alison a young waitress recovering from personal tragedy, begin an affair in Montauk, Long Island that has far reaching consequences for both of them.

Alison attempts to move on from tragedy and build a lasting relationship while contending with the judgment of others and her own self-doubt. Her lover Noah tries to balance the temptations of success, the family he left behind, and the woman he loves. Noah’s former wife Helen attempts to piece her life together while navigating divorce proceedings, caring for her children, and her parents’ noxious influence. Cole, Alison’s former husband, struggles to overcome past heartbreak and start a promising new life. Yet the long-term ramifications of the affair continue to shape these lives, and will lead to an event that changes everything once again.

It's three years later, and Noah, Alison, Cole, Helen and their families are trying to move on with their lives. But the past keeps coming back to haunt them, and the trauma of what they've been through cannot soon be forgotten.

Season four finds Noah, Helen, Alison and Cole in their own orbits, alienated from each other, spinning further and further away from where they all began. Every character is involved in a new relationship, forcing them each to decide if they're ready and willing to leave the past behind for good - a season about new beginnings, tragic ends and the ever-elusive possibility of forgiveness.

The fifth and final season chronicles the aftermath of last season’s horrific events and finds the characters coming to terms with the consequences of their choices – as they make the realization that if they really want to change their futures, they must first face the past. Helen begins the season involved in an intoxicating new affair. Noah meanwhile has to swallow his pride and his jealousy and step in to take care of his family in her absence. But just when things seem to have stabilized, a chance encounter with someone from the distant past sets in a motion a sequence of events that brings them both to their knees.