The Possession Diaries revolves around Rebecca Clarkson, a college student who decides to conduct an experiment with her friend, finding out if the infamous Ouija board can actually contact spirits. She sets up a webcam to document the entire process and invites her friends to partake in the experiment. However, things quickly escalate when a malevolent demon begins to possess Rebecca, causing her to behave erratically and violently.
As the possession intensifies, Rebecca struggles to maintain control of her body and mind, while her friends begin to realize that they may have unleashed something beyond their comprehension. With the webcam capturing every terrifying moment, Rebecca's possession becomes a spectacle for a growing online audience as they watch in horror as she spirals further into darkness.
The film is a found footage horror movie, utilizing the webcam footage to create a sense of realism and immediacy. The Possession Diaries explores the power of the Ouija board and its potential to open doors to malevolent forces that threaten to consume those who dare to dabble in the occult.