It turns out the house is home to two members of the old dictatorial guard... Apparently secret police types or something. They have aged quite a bit, and need young people for their experiments. Being no longer able to hunt subjects down, they use the internet to lure people to their home.
I wont get too much into the story, as frankly it got a little convoluted. This might be due to some disinterest on my part. Eventually there are some zombie types running around, and the old men's goals are a little hard to divine. Of course part of the horror, which is more evident in the next film discussed, is that nothing is scarier than bat-shit-crazy "normal" people. The subtitles distracted me a bit as well; the film is in Spanish.
Penumbra (also Adrián García Bogliano, 2011) is a better effort, in my opinion. It is a classic with a bit of a twist. The feel is very much like Rosemary's Baby or a Dario Argento film, but ultimately the payoff is like When a Stranger Calls.
Our heroine is from Spain, on a business visit to Argentina. She and her sister own a property there which she hopes to rent, and is scheduled to meet a realtor. Things get creepy fast, as we learn of the pending solar eclipse occurring that day, and as the neighborhood people start getting a little wacky. The realtor's staff starts showing up, and the tension builds nicely. Frankly, I knew the whole time who the bad guys were, but the reveal was nicely done, and still gave me the little "oh shit" moment you need from this kind of film.
This one is also in Spanish, but the subtitles seem to be managed better. The problem is that there are lots of little visuals that we non-Spanish speakers seem to miss while looking at the bottom of the screen. I am tempted to watch it again and ignore the subtitles altogether. This one is well worth your time.