For as long as they can remember, Mac, Lina, Milo and Avery have celebrated Family Week together in "the smallest, gayest town in the world"--Provincetown, Massachusetts.

But this summer, their big rented beach house feels different. Avery's dads are splitting up, and her life feels like it's falling apart. Milo's flunked seventh grade, which means everyone is moving on to bigger and better things except for him. Mac's on his way to a progressive boarding school that lets transgender kids like him play soccer, but it means leaving his twin sister, Lina, and his moms--and the safety of home--behind.

Everything is changing, and for Lina, it feels like it's happening with or without her. Avery, Milo, and Mac know this is going to be their last summer together. But Lina can't accept that--and if she can make this the best summer ever, maybe she'll convince them that there will be a Family Week next year. Good things might not last in the real world, but they do in P-town.... Right?