Jane Austen is batting a .6 with me at this stage. I really liked Pride and Prejudice, not so much Emma or Sense and Sensibility, but then I enjoyed Lady Susan and I loved Northanger Abbey! What a lot of people do not seem to get about this novel is that Jane wrote it when she was just 28, and still very much a playful youngster in many ways. It was her first real novel that we know of, but it was put aside as she worked on others. Though she began re-writing it later in life when she was more than a decade older, she died before she could finish it.
The story revolves around Catherine Morland, in her late teens, and fortunate enough to be invited on a trip to Bath (evidently one of Austen's favorite locales) by the Allen family. It's there that she meets two men, the thoroughly detestable James Thorpe, and the delightful Henry Tilney. While Thorpe pursues the naïvely oblivious Catherine, she finds herself very interested in Henry and his sister Eleanor.
In parallel, James has a sister Isabella. They are the children of Mrs Allen's school friend Mrs Thorpe, and Catherine feels quite happy to be befriended by Isabella who seems to be interested in Catherine's brother John - that is until she discovers he has no money when she, like Lucy Steele in Sense and Sensibility, transfers her affection to the older brother - in this case, of Henry Tilney. Captain Tilney, not to be confused with his father, General Tilney, is only interested in bedding Isabella, who is in the final analysis every bit the ingénue that Catherine is. Once he's had his wicked way with the girl, she is of no further interest to him whatsoever.
Meanwhile, Catherine manages to get an invitation to Northanger, the Tilney residence. Catherine is a huge fan of Gothic novels, and Ann Radcliffe's potboiler, The Mysteries of Udolpho is mentioned often. Arriving at Northanger, she is expecting a haunted castle with secret passages, but everything turns out to be mundane - the locked chest contains nothing more exciting than a shopping list, and General Tilney did not murder his wife.
Henry Tilney is a lot less miffed with Catherine in the book than he was depicted as being in the 2007 movie starring the exquisite Felicity Jones and the exemplary JJ Feild, but as also in the movie, the novel depicts a lighter, happier time with General Tilney absent, but when he returns, he makes Eleanor kick Catherine out the next morning to travel home the seventy miles alone, which was shocking and even scandalous for the time, but by this time Catherine has matured enough that she's equal to the burden.
It turns out that the thoroughly James Thorpe (much roe so in the novel than in the movie), who had been unreasonably assuming Catherine would marry him, only to be set straight by her, has lied to General Tilney about her, and whereas the latter had been led initially to believe that she was all-but an heiress, he now believes her to be pretty much a pauper and a liar.
Henry bless him, defies his father and makes sure that Catherine knows (as does Darcy with Lizzie!), that his affections have not changed which (as was the case with Lizzie). This pleases Catherine immensely. Despite initially cutting-off his son, General Tilney later relents, especially when he realizes that Catherine has been misrepresented by Thorpe.
There are a lot of parallels in this book with the later-written Pride and Prejudice. You can see them in the dissolute soldier (Captain Tiney v. Wickham), the rich suitor (Tilney v Darcy), the break and remake between the two lovers, the frivolous young girls (Isabella v. Lydia) and so on. Maybe Northanger Abbey is, in a way, a dry-run for the later and better loved novel, but I think that Northanger Abbey stands on its own. I liked it because it seems to reveal a younger and more delightfully playful author than do her later works. I dearly wish there had been more novels from Austen from this era. She could have shown today's YA authors a thing or two, but I shall be content with this on treasure.