At the start of Oswald's story (after a brief, Boschian prologue), his biggest problems are finding enough people to harvest his barley crop and rent his holdings. After the Great Mortality of 1348-1349, the peasantry will go to whoever will pay them the most. Then a girl's body is found in the woods of the de Lacy estate. It's clear she's been murdered, but the village priest starts ranting about dog-headed people.
Plague Land is a welter of conflicts for Oswald. He has to contend with his hysterical and sinister village priest, his bloodthirsty neighbor who wants to marry Oswald's sister, an ally who keeps disappearing, and a village full of secrets that no one wants uncovered. Of course, Oswald investigates by metaphorically turning over as many stones as he can find. Each new discovery alternate fills him with horror or pity.
After a few chapters, it's a little hard to keep track of what's going on. The initial murders, which consumed Oswald's attention, get lost in the shuffle. The fact that the characters speak relatively modern English makes the whole thing hard to swallow as a medieval mystery. I was hoping this book would be another Owl Killers, but I was disappointed.