"Dazzling, delicious and delightful," says the front cover in a quote from Karen Hawkins. Well, no, I don't agree with that description of Always a Scoundrel, although it has some moments of charm.

Could a young boy actually be a wizard with a tame owl? Could Mr. Darcy really defy family expectation and marry Elizabeth Bennet? The key to plunging deep into a story and being taken to another place is plausibility. It may be odd or unexpected, but if the book writes the situation well enough, we can believe it.

The problem with Always a Scoundrel by Suzanne Enoch is that I found two central premises entirely implausible. She's working hard at a new-ish angle on the reformed rake type of story, but unfortunately I was in no way convinced why the rake, Lord Bramwell Johns, was reformed by heroine Rosamunde. Even less believable is the strange plot of the Duke of Cosgrove to marry Rosamunde in order to degrade her. Why is he so keen to do that? It just doesn't add up at all. As a result, I spent most of the book not believing in the situation in which the characters found themselves. That doesn't make for satisfying reading.

I was even less convinced that Rosamunde, a gently-bred woman from the aristocracy, would (a) understand the rough words that Cosgrove says to her (to be insulted by them), and (b) decide to behave in quite the way she does to spoil his prize of a virginal bride. Some things feel like they could only happen at the pen of an author, rather than in real life.

Despite these rather glaring problems, the story does improve as the tale moves along. The final third of the book, where Bram is trying to reform and rescue Rose from a potentially disastrous marriage, is much more satisfying. I still found implausibility everywhere and felt that Bram's final method of dealing with Cosgrove is rather un-heroic, but it's at least more interesting a story at that stage.

As a reader, I find it hard to appreciate rakes, reformed or otherwise, and Bram is no different. His former wild lifestyle didn't appeal to me, and I wasn't entirely convinced that Rose could keep him on the straight and narrow - or indeed why her influence so changed him. This is fiction, and it is escapism and fantasy. For this reader, however, a little more plausibility would have gone a long way.

• A Lady's Guide to Improper Behavior
• The Care and Taming of a Rogue
• Before the Scandal: The Notorious Gentlemen
• After the Kiss: The Notorious Gentlemen
• Sin and Sensibility
• The Further Observations of Lady Whistledown