Dorian Rusk inherits a blood debt that will claim his wife and first child, and he signs a covenant letting another woman carry it so that Blythe, the girl he believes once waited outside a lighthouse until dawn, can live. He picks Carys Bell, a broke scholarship applicant caring for her blind grandmother, and forces the marriage by holding the old woman. Carys bargains three rules and begins to trust him, not knowing each line on the copper plate is being pressed dark in order: her breath, her bloodline, and at twenty-eight weeks, her name. Blythe turns the last key herself. Carys bleeds, her child is lost, and a forged death notice is filed, but a transport crew finds her alive. Six years later she is a researcher tracking the emergency transfers that failed her, engaged to Wesley Shaw, whose funding secretly comes from Dorian. Dorian learns she survived and starts buying his way back into a life he nearly ended, while Alden, the uncle behind the lie, turns Wesley into a weapon.
