Riveting start to what turned out to be a very fine trilogy. The localised (Basque) setting is very effective and the moody atmospherics of the area are visually very well caught. As seems to characterise dark European thrillers (non-Nordic variety) remote villages have long-hidden secrets which it seems only a returning native is able to discover.
The relationship between the lead investigator and her husband is very finely done and gives a touching a subtle portrait of a relationship. Her mother on the other hand seems a pretty grim figure (she is but writing this as comments as if only seen film writing about).
By the ending of the film , mysteries had been partially solved but everything is very well and effectively set up for a natural continuation. there seem to be hints that the mystery is wider-ranging and more far-reaching than at first seemed.