Wrapping up Randal's story. More spoilers ahead, because these two, like the first two, are tied strongly to the earlier ones, and each other.
In Castle, Randal and Walter are escorting gold to the siege of Bell Castle, which has a magical bell, rung every hour, that keeps anyone but the castle wizard from casting magic within it. And the Lady Blanche is held there -- the last living . After a magically aided sally, the gold is stolen, leaving Randal with no abili. His investigation of what happen -- the Castle's people stole it through a portal -- triggers a trap. The rest involves single combat, a secret marriage, a revelation about the royal family, a hedge witch, a prisoner, and much more.
In Daughter, Randal, Walter, and Lys are escorted to Elfland by Madoc -- who can't come with them. They must go alone to bring back the High King's daughter and rightful heir. And once within, Randal finds that what superficially looks beautiful is tarnished and flawed. And the Erlking promised to keep her safe. . . this story involves Lys playing the king, Walter's asking for a ransom with care, Randal's truthfully describing a banquet as the worst food he ever ate, a loophole in a magical circle, illusions, and much more.