Collider:
Ultimately The Possession lives and dies on the relationship between its two leads: Jeffrey Dean Morgan and Natasha Calis. As Clyde and his youngest daughter Em, the twosome’s bond forms the backbone of the film. Clyde, has for all intensive purposes, completely screwed up his relationship with wife Stephanie (Kyra Sedgwick) and eldest daughter Hannah. The one person who looks or treats him with any sense of fondness is his youngest daughter, Em and Clyde is intent on keeping this so. So imagine his chagrin – when Em gets taken over by an evil Jewish demon in a box and begins to violently distance herself from him. Clyde is then forced to result to increasingly elaborate and dangerous means to bring his daughter back and repair their fractured relationship. (Cinema, Jeffrey Dean Morgan, Natasha Calis, The Possession)