Laura (Rueda) has returned with her husband (Cayo), to the orphanage where she was raised, with the aim of turning it back into a home for children with special needs - such as her son, Simon (Prinvep), who is HIV-positive, and doesn't know he was adopted. Without any playmates, he has invented a whole roster of imaginary friends. However, these start to take on a darker aspect, including a boy whose head is covered in sack-cloth, an image which stirs long-repressed memories in Laura. Then, one day, Simon vanishes: over the ensuing months, despite desperate efforts, his parents fail to find even a clue, until they turn to a medium, who opens up some doors - both literal and metaphorical - that might have been better left closed.
This is one of those old-school horror movies, reliant more on suggestion than explicit gore (despite one shock, lifted wholesale from Final Destination), and like most of its kind, the effectiveness is something of a mixed-bag. Some elements of the story don't really stand up to scrutiny, and the use of a conveniently-omniscient medium is weak. That said, there are certainly moments which certainly do generate the expected level of creepy tension, and Bayona has his share of directorial skill. Rueda is a convincing heroine, but Cayo has very little to do and it feels more like remake of a Japanese film, with the obligatory ghostly child, lurking in the shadows for purposes that are more dramatic than plot-driven. While not without merit, I didn't find enough here that was new or interesting enough to make it particularly memorable.