Megan is convinced that having exchange student Isabella move in with her family is the worst thing that has ever happened. Little does she know, her intense friendship with Isabella will have life-altering consequences.

In the summer of ’99, Megan keeps Isabella at arm’s length while Isabella and Luke grow closer. Meanwhile, in the winter of ’99, Megan and Isabella deal with the aftermath of the sex tape and come to a surprising decision.

Megan and Isabella find common ground during a cabin getaway with the boys in Summer '99. It's starting to look like the beginning of a beautiful friendship...but a lot can change in a year. In Summer 2000, Isabella and Megan find themselves in hot water. As they put together their respective legal teams, they realize the only way out may be sinking the other.

Under Isabella's influence, Megan decides to break free from her good girl image with a new look and a fake ID. And as Jeff takes an interest in Megan, Luke begins to see her in a new light. Meanwhile, tensions between the Landrys and the Chambers reach their boiling points as revelations about the sex tape unfold.

An old flame from Isabella's past comes to Chatham, threatening to reveal buried secrets. Meanwhile, in Summer 2000, Megan's dirty laundry is aired in front of the whole town.

Megan throws Luke a seventeenth birthday party to remember. Meanwhile, in Winter '99, Luke crosses a line with Isabella at the annual Chatham Plunge. And in Summer 2000, as Megan gets deeper into her questionable work with Ned, the town recluse, Isabella's own run-in with the law comes to light.

Summer love is in the air as Megan’s and Luke’s feelings for each other finally come to the surface. And as the countdown to Y2K begins at the New Year’s Eve Party, Megan isn’t sure who she can trust when Luke and Isabella get caught in a game of "he said/she said".

Now that Megan and Luke have gone public with their new romance, Isabella feels like a third wheel. Is she losing Megan? After the New Year’s Eve party, Megan and Isabella come together to confront Luke about his bad behavior, only for things to get desperately out of hand.

As his relationships with Megan, Isabella, and his family come to a dangerous head, Luke is forced to reckon with his past and come to terms with the fact he might not be such a “good guy” after all.

The walls are closing in around Megan and Isabella as their friendship is put to the ultimate test. And when the surprising and devastating truth about what really happened on New Year's Eve is revealed, no one will ever be the same.