A kingdom's fate. A magical contract. And a demon's bride bound by a terrifying vow.

To save her people, a mortal woman is offered as a sacrifice to the ruthless Demon King, bound to him by a set of ancient and dark vows. She enters his desolate kingdom as his captive, ready to defy the monster who rules it. But the Demon King is not the heartless tyrant of her nightmares. He is a king trapped by a curse, and the dark magic that binds them is slowly consuming them both.

Their enemies to lovers journey begins as they are forced to work together to survive. As they unravel a dangerous plot that threatens to destroy both their worlds, she finds herself drawn to the man beneath the monster's mask. But every touch, every shared secret, and every act of defiance against their ancient pact only tightens the chains of the dark vows that bind them.

Can a mortal heart break the dark vows that hold them captive, or will their forbidden love become their ultimate ruin?