When Fitzwilliam Darcy's sister lies dying from a magical ailment, the only person who can help is Elizabeth Bennet, the powerful Librarian of the Great Library – the same woman he abandoned five years earlier. Elizabeth can't forget Darcy's refusal to believe in her magical ability, even now that she has a griffin familiar. However, as the Librarian, duty compels her to help him. Together, they undertake a quest to the Faerie Realm to find a cure, encountering dangerous magical creatures along the way. An even greater danger lurks in their own hearts.

Patience Whitford spent the last two seasons watching her elder sisters make grand matches. She is thoroughly apprehensive with the notion of being limited by marriage. But that seems like an inconsequential concern with no prospects on the horizon to follow in her sisters' footsteps. And to make matters worse, she is uncommonly jealous of all of the military officers she's befriended and their grand adventures. When Major Ashley Stuart is assigned to investigate some petty crimes near his brother's estate in Greenwich, it soon becomes apparent that there is something much larger going on.

Much to her father's dismay, Miss Amelia Buxton aspires to become a spinster, just like her eccentric aunt. Growing up with parents who married for every reason but love, she has never seen a joyful marriage. When Amelia requests a summer trip to the legendary waters of Brighton, her father allows her the excursion, but with one requirement: She must return engaged, or agree to the proposal of the man of his choosing.

Lady Evangeline Raine prefers animals to people and has no interest in marriage—much to the dismay of her flirty younger sister, Viola. Because their father has one rule: Viola may be courted, only if Effie has a suitor as well. Saddled with debt, Gage Croft, Duke of Vale, is determined to rebuild his estates. When the owner of his vowels offers him a fortune to charm the impervious Lady Evangeline for the season so Lady Viola can be courted, the game is on, even if it means pretending to seduce an unconventional wallflower.

American heiress Emma Dunster has always been fun-loving and independent, with no wish to settle into marriage. She plans to enjoy her Season in London in more unconventional ways than husband hunting. But this time Emma's high jinks lead her into dangerous temptation. Alexander Ridgely, the Duke of Ashbourne, is a notorious rake who carefully avoids the risk of love until he plants one reckless kiss on the sensuous lips of this high-spirited innocent and condemns himself to delicious torment.