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 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.

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.

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.

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?