Pirate Girls by Penelope Douglas

She’s the daughter of Jared Trent. He’s the son of Madoc Caruthers…

Kade and Hunter Caruthers.
Brothers. Twins.
My cousins.
In a way, they’re my family. Protective. Indulgent. My best friends. But there was something else there, too. That ever-present whisper that reminded me more as I got older that we didn’t actually share any blood.
They used to be inseparable. We all were, but not anymore. I don’t know why Hunter left or why he joined a rival team in Weston—that Rebel town across the river—to stand on the opposite side of the field from his brother, but Kade is out for blood now and Hunter has finally decided to engage.
Rivalry Week.
Parades. Parties. Pranks.
And the Prisoner Exchange.
Weston will send a hostage to our school, and they’re taking me. I’m Hunter’s for two weeks. In a dilapidated brownstone on a nearly abandoned street with almost no supervision.
Ten days in an enemy school. Fourteen nights in a town full of bullies with no curfews and no rules.
And Hunter has no intention of protecting his little cousin anymore.
The Pirates will come for me. How can they not? A Pirate never sits out on the fun.
But I never needed protection or rescue, because a Pirate never runs, either.