'What the river knows' is a YA historical fantasy, with little emphasis on the fantasy. Actually, the magic system was more or less an afterthought, was not explained at all how the magic worked and how it was connected to the past, and it was used sporadically as a plot device.

The main story, on the other hand, and though there were some predictable twists, was enjoyable and a nice mystery with lots of suspects.

The romance, however, was too instant and with no pace.

Nevertheless, the characters were interesting.