Third and final book in the Green Knight's Squire trilogy. Serious spoilers ahead.
As in, it opens with Nerea tending his injuries after the disastrous fight that ended the last one. It ends with her getting him back to his mother. Where she is deeply revealed to learn that he has sworn to King Arthur, but tries to forbid him to go to the Green Chapel as he had promised. Then he's arrested by a mysterious government agency where his police badge does him no good. And he has to escape within a day to possibly keep his promise.
With great attention to detail, he pulls it off. And then he sets out. It involves a three-headed dog, summoning his father's boat, a strange restaurant, a covered bridge, defending his mother's good name before the elf kings, and more.