The series has revolved around a conflict between title character, faerie princess Meredith NicEssus, and her cousin, Cel.

Cel's mother, Queen Andais, has promised that the first of the two cousins to produce a child will become ruler of the Unseelie Court.

Mistral's Kiss continues to follow Meredith's attempts to bear a child and to avoid Cel's various schemes.

Before they can escape, they are confronted by Sholto, King of the Sluagh, and Lord of That Which Passes Between, and his two night hags, Agnes and Segna.

Meredith conjures a protective covering of four-leaf clover and discovers a "thin place" that allow them to escape the Sluagh sithen.

Now in the real world, Meredith calls on a group of Red Caps (cousins of the goblins), led by Jonty, to fight the Wild Hunt with them.

After the battle, they are rejoined by Galen, Aisling and Nicca who, having disappeared from the garden, reappeared in the Hall of Mortality.

Galen's wild magic causes flowers and water to appear in the Hall, and he accidentally causes all prisoners to be freed, including Cel, the Queen's son, who wants Meredith dead.