It is 1509 and, for the people of the Burren in western Ireland, the Michaelmas Fair is a joyous time for trade and celebration, signaling the start of autumn. It's a chance to gather, buy and sell their wares, and pay tribute to the lord of their clans. But this year is different. The greedy steward of the MacNamara clan has decided to raise the amount demanded for its tribute, and it's not long before tempers are running high.

When the steward is found beaten to death in the local churchyard, it falls upon Mara, the Burren's Brehon Judge, to piece the puzzle together. Was it revenge, greed, or something more sinister that motivated the murder? When another body is discovered and alleged a suicide, Mara is unconvinced. And despite the distraction of a surprising offer of marriage, it is up to her to bring the killer to justice before there can be yet another death.