I've been encouraging everyone I know to go see it, and also telling them: don't read the plot synopsis. You only get to see it the first time once.
However, the work is a lot easier to understand if you can follow the family relationships. Joshua Kosman helpfully posted a family tree and some explanations to opera-l back in 2000, which must have been the last time SFO brought up this piece. Herewith the family tree and his notes (Feedly is garbling the family tree, so if you are reading this post with Feedly or an RSS reader, click through, probably on a laptop or desktop machine):
GRANDMOTHER BURYJA had two sons (both deceased) | |--------------------------| | | | | KLEMEN -----BURYJA 1st wife---TOMAS BURYJA---2nd wife (widow) | (a miller) (unnamed) | KOSTELNICKA | | | | | | LACA STEVA BURYJA JENUFA (half-brothers) [Joshua's notes: The one point that got squeezed out of my version [of the family tree] is that Laca is Widow Klemen's son from her first marriage. The editors also append these helpful notes: Steva is Grandmother's real grandson. Laca is Grandmother's step-grandson. Kostelnicka is Grandmother's daughter-in-law. Jenufa is Kostelnicka's stepdaughter and Grandmother's real granddaughter. ]
1. Steva is due to inherit the mill because he is
Buryja's son from his first marriagein the direct male line. The Widow Klemen is Burjya's second wife; Laca is her son from her marriage to Klemen. (Laca and Steva are both Widow Klemen's sons.)
2. Jenufa loves Steva. Note that they are first cousins: their fathers were brothers.
3. Laca loves Jenufa. They are not related by blood.