Like Janet McNaughton's An Earthly Knight, this is a fairly straight retellingof "Tam Lin"; it's set in 19th-century America, and the heroine is a farmer's daughter named Janet, who falls in love with the mysterious Tom Linn and must then rescue him from the queen of faerie.
Ipcar follows the plot of the ballad so closely that there are really no surprises for most of the book. In fact, I was just becoming rather bored at its lack of innovation when, two-thirds of the way through, the rescue begins — and that's where it gets interesting. Janet enters a nightmare world of forest, river, and circus — yes, circus, where Janet ends up after pulling Tom off his horse. It sounds odd, but it works surprisingly well, at least for me, and it was frankly a lot more interesting than the rather dull retelling given in the beginning of the book.
If the whole book had been as original as the end, I'd call this a very good Tam Lin retelling; as it is, one must bear with the standard beginning for the sake of the intriguing ending.