The Bitter Yield

The river-clan’s longhouse stands above a flooded valley, its plank floor damp and its clay vats lined up beneath a smoky rafters’ loft. At dawn, the clan’s adult members—among them Iara, 34, and Bento, 41—produce a pearly fluid they call the yield. It looks like milk, but it is a living ferment: left untreated, it swells into a bitter foam that can split a storage vat and poison the river’s fish. Three vats have already started to bubble. The spring flood has cut off the nearest trading post, and the clan’s winter stores depend on stopping the spread before nightfall.

You are the traveling fermenter summoned to diagnose the batch; the clan has given you one worktable, a pile of strange reed filters, and until sunset to make a usable test. Iara, the keeper of the vats, wants a method she can repeat without you. Bento, who brought you here, insists the yield changed after a sealed clay jar was found lodged in the riverbank—and keeps trying to hide its cracked lid. The clan needs your expertise, but its members will not hand over their only food supply on guesswork.