Sophia and Angela live in the Northern and Southern United States, separated eight years ago after the second civil war. Sophia's an atheist, attends pride rallies with her dads, and mostly doesn't see a problem with the Northern way of life, because she's been brought up that way. Angela's a devout Christian with a passion for country music, and disapproves of Sophia's fathers' way of life, because she's been brought up that way. Sophia lives outside Boston, the capital of the Northern United States; Angela lives in a small town on the outskirts of Nashville, Tennessee, the capital of the Southern United States.
When Sophia is selected by her school's chapter of the Union Project, a project devoted to fostering cooperation between the two nations, to be one of a few exchange students for her school and to Nashville, she's plunged into a world completely different from anything she's ever known. Football every Friday, sweet tea in every restaurant, and if you don't go to church on Sundays, people wonder if you're an atheist. She learns to genderbend her father Andrew's name to Andrea, and tactfully answer questions about how many people in her school hook up at every party, and how frequently they drop f-bombs — and to absolutely nevermention her friend who had an abortion.
And as Sophia spends more time in the Southern US, she's forced to confront that perhaps her worldview isn't as "open-minded" as she would like to believe.