This Catalan chiller which, like 2008's superior El Orfanato, stars Belen Rueda, likewise benefits from Guillermo del Toro using his name as a powerful Spanish cine brand on the poster.
Rueda plays twin sisters Julia and Sara. Both suffer from a progressive deterioration of their eyesight. Julia has 80% of her vision left at the start, but is prone to stress-related attacks which will tend to lop off further fractions.
Meanwhile Sara is already blind during the opening sequence in which we witness what the cops interpret as her suicide by hanging — but then they didn't see that foot kick the stool out from under her.
Julia suspects foul play and is determined to investigate. Husband Iván however appears to want a quiet life, partly because of Julia's known tendency to suffer seizures, and partly because he has copped off with Sara at some point in the past.
Guillem Morales starts off well enough, delivering a highly suspenseful first hour, which successfully suggests much of the mood of supernatural horror, without ever leading us to doubt that Julia's adversary is a man of flesh and blood, albeit one with an uncanny — and plot relevant, though mostly only poetically — ability not to be seen by people he walks right by.
The director might overuse the 'look who's behind you' scare a bit too readily, but there are some implementations of the visually-impaired horror trope I hadn't seen before: such as Julia's eavesdropping on the bitchy conversation of a group of blind women (played almost as undead!) at a social club for the sightless. There's also a creepy neighbour who functions a bit like Christopher Lee in The Resident, i.e. as a rather too obvious red herring.
During this opening sixty minutes Iván is kind of in the way, because he has to keep leaving Julia on her own in order for her to wander into darkened spaces where her failing vision is going to add to her (and our) growing sense of vulnerability. So — spoiler alert — Iván is removed from the scene permanently around the mid-point, yet instead of ramping up the tension, this is really the point at which the movie goes a bit awry.
Morales and co-writer Paulo have to an extent under-exploited their material early on, but have nevertheless managed to keep the tension up nicely enough. With Iván gone, they really let go and we had the sense that too many new or at least suspended narrative ideas were being crammed into the final third. For example, it's as if they suddenly decided to stop showing us the faces of everyone we're supposed to start being suspicious of, such as Julia's ophthalmologist.
And this is a pity, because they really needed to focus on their villain and his own visibility issues in order for the conclusion to be meaningful as well as more than a collection of twists and set-piece frights.