Y/N Novak has spent her entire life caught between two worlds. As Castiel's daughter, she possesses strange angelic abilities she barely understands, making her a target for both Heaven and Hell. After moving into the Men of Letters bunker during Season 12, she becomes an important part of Team Free Will, hunting alongside Sam, Dean, Castiel, and the newly arrived Jack Kline. Dean Winchester never expected to grow attached to someone the way he does to Y/N. What begins as concern for his best friend's daughter slowly turns into something deeper as they spend more time together on hunts. Torn between his feelings, his loyalty to Castiel, and the dangerous life they lead, Dean tries to keep his distance. Meanwhile, a powerful celestial enemy begins hunting Y/N for the grace hidden within her bloodline. As secrets come to light and old enemies resurface, Dean and Y/N find themselves fighting not only for their lives, but for a future neither of them thought they could have. With Heaven in chaos, Jack learning to control his powers, and darkness closing in from every side, they'll have to decide whether love is worth risking everything they've ever known.