After her parents get divorced, sixteen-year-old Rosalie moves to Massachusetts to live with her mom. It’s there she meets Alexander, a mysterious boy with a life-threatening secret, and falls head over heels for him, despite promising him it would be the one thing she’d never do. But as Rosalie slowly starts to unravel the truth, she’s faced with the stark reality of what loving Alex really means, and whether she’s strong enough to endure it.