They had a plan, her and Lyall.
Well, mostly her. Daphne loves her youngest clan-brother, but he doesn't have an ounce of guile in his body. In a still-human Potential, it was sweetly innocent, an attractive quality. In a vampire, a death sentence. So: Daphne had a plan for how they were going to get out of this situation alive, because she would rather not be sacrificed on the altar of the blood feud between their sire and a rival clanlord.
It didn't work.
Or, it half worked, because Lord Greenstone was, as predicted, horrified to discover that their sire had sent a graceling—a baby vampire, not yet a year past his Turning—as a blood price. Not only did he refuse point-blank to kill Lyall, but he also took him under his protection, arguing that their sire had clearly failed in his duty. Daphne had been trying to convince Lyall of that exact point for most of the last two days.
The only problem was that Lord Greenstone still needed a sacrifice for his blood feud. No one could argue he wasn't justified in seeking a blood price for the murder of his sire and clan-brother, nor that Lord Whiteraven wasn't justified in offering his scions—other than Lyall—as payment for his own sins.
Daphne has been a vampire for five years. Too old to have a graceling's protection from the harsh justice of the clans. Too young and inexperienced to come up with a clever way to save herself, not just her baby brother.
Lord Greenstone has the mercy to make it quick. His quarrel isn't truly with her, after all.