Adoptive parents Adrián (Jordi Mollá) and Claire (Catherine McCormack) grow increasingly concerned about their adoptive daughter Isabel's imaginary friend Stevie when the unseen playmate begins turning their lives upside down. When having a child proves psychically impossible for loving couple Adrián and Claire, they decide to adopt six year old Isabel, a sensitive child with a troubled past. Shortly after welcoming Isabel into their home, however, the proud new parents discover that their adoptive daughter's imaginary friend Stevie seems to have a nasty mean streak. Later, when Claire discovers that Stevie is more than a figment of her daughter's imagination, she embarks on an obsessive quest to learn exactly why he has taken up residence in their home. Only then will she finally lay the past to rest, and find the strength to give Isabel a happy childhood.