The novel opens with Elizabeth settling in at Pemberley, awaiting the birth of her first child and trying to figure out how make her new role as mistress of Pemberley her own. She is constantly reminded of her husband's late mother, Lady Anne, by both the house itself and the servants, and worries how to measure up. When she moves an old writing desk and discovers a letter written from Lady Anne to her future successor, it is the beginning of a mystery involving a missing family heirloom.
First, however, the Darcys head to Bath to interview a doctor who will attend the baby's birth. This gives us some good Bath scenes—filled with lots of repartee between the spouses—as well as chance to introduce Capt. Frederick Tilney into the story. Tilney sees Darcy's name in the Pump Room book and invites him to Northanger Abbey, claiming that their mothers were friends and wanting to renew the connection. The Darcys agree, but upon arriving at the Abbey find conditions very strange. There is a lack of servants—and their own attendants mysteriously disappear, and are later discovered to have been drugged—their host doesn't show up for their substandard supper; when they do meet Tilney, they find him severely injured but in good spirits, asking strange questions about their mothers and hinting at the search for a family secret.
Tilney's behavior seems especially peculiar, considering that when the Darcys mention they have found personal belongings in the late Mrs. Tilney's rooms where they have been lodged—a set of diamond jewelry, to be exact—Capt. Tilney doesn't seem interested. The reason seems clear when the Darcys cut their visit short, and within hours are accused of stealing the Tilney diamonds. The jewels are found in a clever replica of Darcy's walking stick, and Darcy is charged with the crime by an overzealous magistrate who won't consider the possibility he has been framed. He is especially disinclined to release Fitzwilliam after Henry Tilney shows up and says that Capt. Tilney died some time ago, and he never heard of the housekeeper the Darcys met.
The Darcys are forced to call on Lady Catherine de Bourgh to get him released, and she returns with them to Pemberley. Elizabeth must deal with her constant disapproval and interference, even as she goes through Lady Anne's old letters to see if there really was a friendship between her and Mrs. Tilney, and thus find some clue as to why their visit to Northanger Abbey went awry. She finds the friendship was real, and is somehow connected to Lady Anne's missing family heirloom, and she and Darcy manage to unravel all the mysteries (and thwart Lady Catherine) whilst preparing for the new baby as well.
I thought this was the best mystery of the series so far; there were no supernatural elements to cloud the mystery (Elizabeth thinking she feels Lady Anne's spirit had little to do with the mystery plot), and the connections between the Darcy family and Tilney family seemed logical. I thought Henry Tilney's character was different than how Austen portrayed him in NA—he showed none of the quirky wit that made him interesting—but then, he's introduced in a very tense situation. Other Austen characters are involved in the mystery in a very organic way, and the Darcys' relationship continues to show affection and witty banter, so that's a minor quibble. The scenes in Bath and at Northanger Abbey have much the same feel as the original Austen, as well. So I'd give this sequel—one of the very few to NA—an unqualified thumbs up.
Next up: Mansfield Park. (And yes, I meant not to use an exclamation point. Sigh.)