It's been five years since Maggie James followed her screenwriting dreams to Los Angeles. But things in Hollywood didn't go quite to plan. Now, suddenly, she's back home in New York, and some of the high school friends Maggie abruptly left behind are more willing than others to welcome her back into the fold. Maggie doesn't know who she's more anxious to see: her ex, Mac, or her ex-best friend, Liz. For Liz, Maggie - the girl who abandoned her at the worst possible moment - is the unwelcome surprise that could derail her perfect summer. Liz is recently engaged to her high school sweetheart Cam, but Maggie's arrival has old wounds bubbling to the surface, exposing the cracks in Liz's perfect-to-plan life. Maggie accepts the invitation to get in on the group's Fire Island share house, named Serendipity. For three weekends this summer, this tight knit group (+ Maggie) will descend on Fire Island for a few days of the sunny bliss that can only exist in those sepia-toned, Polaroid-captured, mid-twenties summers. And while the old hurts of Maggie's departure have left deep scars, if Maggie is going to chart a new path forward, she'll realize that she'll need the people who have loved her longest. The question is, for Mac and Maggie, and Maggie and Liz... is it possible to find their way back to each other after all this time?