A daughter becomes involved in a series of exorcisms while trying to discover what happened during her own mothers exorcism.
Opening with some video news story of a police investigation showing three murders it quickly moves to present day. The Devil Inside is another supposed documentary footage film with some good sound design and few jump scares. However that's about it. Unfortunately the format and story has been done so many times it's become tiring and this is in the league of The Amityville Haunting (2011) as appose to Paranormal Activity 3 (2011), Rec (2007) or even The Last Exorcism (2010) and Grave Encounters (2011).
As a side note you may want to bring a pen with you for the ending, although it wont help wrap things up when you've viewed the site. As with the Fourth Kind (2009) you know it's not real so it feels pointless to follow bread crumbs as it can't create that willing suspension of disbelief.