This is book 13 of the "Brother Cadfael" series.

This note contains spoilers for the book.

The thirteenth Brother Cadfael book. A woman whose husband and child died after only three years of marriage has given up half her property, a valuable house, to the abbey for a rent of one rose a year from the bush that grows there. She's now busily managing her business -- cloth-makers. Then the rose bush is attacked, fairly shortly before the rent was due, and a monk killed defending it. Then the woman disappears.

There's another death, of a man trying perhaps too hard to advance himself, but at least trying to do good, before it all gets straightened out. The heiress whose whim started the whole chain even get her interest in life reawakened, and finds a man she'll likely marry.