Belly and Jeremiah plan to keep their big news secret from their families until everyone is reunited in Cousins for Susannah's memorial garden ceremony. Everyone, except for Conrad.

Alone in Philly, Belly turns 21. But her special day turns sour when family disagreements about her future take center stage.

All's fair in love and boardwalk games. A day of competition with old and new friends stokes big feelings for Belly, Conrad and Jeremiah, and leads to an even bigger surprise that will affect them all.

It's Belly's first day as a debutante, and a day of shopping and tea parties make her wonder if she made the right choice when she checked yes on Susannah's invitation. But when Cam shows up, things turn around for Belly. Her summer of firsts is just getting started. Meanwhile, Steven's having his own summer of romance, and Laurel is intrigued by a fellow author.

It's the first real day of summer: the day Belly, her brother Steven, and her mother Laurel head to Cousins beach to stay with Susannah Fisher, who's like Belly's second mother, and her boys, Conrad and Jeremiah. Belly's been going to Cousins since she before was born, but something about this summer feels different for Belly. And if the first night is any indication, she's right.

It's Belly's 16th birthday and her best friend, Taylor, arrives in Cousins to help celebrate. Belly's birthday is always her favorite day of the year, but this year she's blindsided by a secret Taylor has been keeping from her. The debs ask Belly who she's bringing to the debutante ball. Laurel and Susannah's secret finally comes to light.

Belly's not the same girl she was at the end of last summer. It's the last day of school, and, after a tough year, Belly tries to let loose with Steven and Taylor, but some things are too big to leave behind.

You don't have to go home, but you can't stay here. Belly and the gang break into a familiar spot for the night after being forced out of the summer house by Aunt Julia. But the change of scenery will force everyone to reckon with their feelings.

Believing that Conrad might act on his feelings for her, Belly makes a decision. But when Belly and Conrad finally get a chance to talk, things don't go as she expected, and she wonders if she's had her eye on the wrong Fisher brother. Steven is assigned to work the poker room at the country club, and Laurel and Susannah have a night out.

School's almost out, and Belly's excited for another idyllic summer in Cousins with her boyfriend, Jeremiah. But her plans go off the rails after she learns a shocking truth.

It's the 4th of July, and the fathers have come to Cousins for Susannah's annual party at the beach house. Tensions flare between Conrad and his father. Belly and the Fisher brothers make margaritas, and chaos ensues. Later, Belly has a romantic moment that's interrupted.

Taylor comes back to town to play in the Cousins Beach charity volleyball tournament, and to help Belly, who's caught between Conrad and Jeremiah. When a yacht party with the debs ends in disaster, Belly's decision between the brothers becomes clear. Steven finds himself in over his head with Shayla's wealthy friends, and Cleveland helps Conrad through an emotional moment.

After a painful revelation, Belly, Jeremiah, and Conrad are trapped in close quarters for the night. Emotions run high as Belly must reckon with past and present to decide her future.

Belly joins Jeremiah on an important search, but when tension over their past threatens to get in the way, they have to find a way to heal their rift in order to help Conrad.

In the wake of an earth-shattering betrayal, Belly tries to pick up the pieces. Caught in the crossfire, Taylor picks a fight with Steven that ends in disaster.

The summer house is for sale, but Belly, Jeremiah, and Conrad won't let it go so easily. While Conrad works on a secret plan, Belly and Jeremiah try a more direct route. But being back in Cousins with the Fisher brothers means Belly can't escape painful memories of the past year.

Some hangovers are worse than others. Belly wakes up to a reminder of the mistakes she made last night. But is it too late to fix everything?

As their time in Cousins winds down, Belly finds herself wondering: What Would Susannah Do? Throw a massive party, obviously. But will the festivities bring them the closure they need, or just stir up new problems for everyone?

The debutante ball is here, but Belly's big night is almost ruined when Jeremiah learns the secret his mother has been keeping all summer. When Belly's left alone on the dance floor, someone else steps in to save the day. With Susannah and Laurel's secret out in the open, the season ends with a promise from Susannah and the confession from Conrad that Belly has been waiting for all summer.