When I first saw this film listed as Spains' entry in the category of Best Foreign Language Film for the Academy Awards on the grid at the New York Film Festival (September 2007), I was excited to see "Guillermo Del Toro presents" tagged to its title. My first thought was about the film Pan's Labyrinth and what a statement it made in the 2006 world film community. In this film Del Toro produced and gave his seal of approval to first time feature film director Juan Antonio Bayona and screenplay writer Sergio G. Sanchez's stylish script.

Movies like Poltergeist, The Omen, The Devil's Backbone and The Others can be associated to this film, but what makes this more than a fancy repeat in the classic genre panoply of haunted houses, ghosts, and parallel worlds is its depth. Rather than dealing with gore, this film carried the audience's imagination into the world of fantasy, from the present day to the past and back.

The story begins at the Good Shephard Orphanage where a 7-year-old girl named Laura (Mireia Renau) is playing a count, hide, and tag game with her orphan friends. At night they are read stories. The children associated themselves to the Peter Pan tale and questioned the character Wendy in the fairytale. They all wonder why Wendy wanted to grow up and the reasons why Peter Pan wanted to remain a child? They all wanted to stay as children and enjoy themselves. All the time Laura is unaware that she is being processed for adoption, which would break up the band of friends. The day arrives when she leaves her friends and the affectionate staff at the orphanage for a new loving mother and father.

Thirty years pass and Laura (Bela Rueda), her husband Carlos (Fernando Cayo), and their adopted son Simon (Roger Princep) — who was born HIV positive and in need of constant care — move into an old building sitting by the sea. This building was the orphanage Laura lived in as a child. Laura and Carlos have plans on refurbishing the facility and opening an institution for disabled children.

The only problem with this ideal family's happiness is young Simon, who does not have anyone to play with. One day he finds imaginary friends to play with and they encourage him to go on a treasure hunt in the house and along the seaside. Laura accepts the thought of Simon's imaginary friends and treasure hunt with apprehension, until the day he disappears. Laura and Carlos are frantic and the local police are called in to conduct a search for Simon. The police cannot find Simon, but Laura recognizes clues that no one else can see. These clues are from her childhood and she starts to see ghosts. She recruits paranormal scientists to help her locate these ghosts who have Simon, and this opens the door to a parallel abnormal world of her past.