Horror movie The Possession Of Hannah Grace shows what happens when an exorcism goes terribly wrong. In most exorcism horror movies, the possession of some poor soul is usually the main focus but in The Possession Of Hannah Grace, it’s only the beginning. Directed by Dutch filmmaker Diederik van Rooijen, the film offers a fresh spin on the demonic possession genre by focusing on the aftermath of a failed exorcism of a teenage girl.

The Possession Of Hannah Grace opens with a scene depicting said failed exorcism. Hannah Grace (Kirby Johnson) is tied to a bed while contorting impossibly and growling demonically as two priests attempt to rid her of the demon that has possessed her – signified by one of her eyes turning a piercing, bright blue. Hannah’s father Grainger (Westworld’s Louis Herthum) pleads with his daughter to fight the evil inside, but the demon takes over and makes her brutally kill one of the priests. Before the possessed Hannah can kill the other priest, Grainger smothers her to death with a pillow.

Related: As Above, So Below’s Twist Ending Explained: They’re In Hell

Enter Shay Mitchell of Pretty Little Liars fame as Megan – a former police officer just out of a stint in rehab who takes a job working the graveyard shift at the morgue that receives the mutilated body of Hannah. Weird stuff starts happening like Hannah’s morgue drawer not staying shut and a swarm of flies congregating around her corpse. Soon enough Hannah’s corpse is going walkabout and killing people left, right and center as Megan tries to stay alive.

Morgan in the morgue in The Possession of Hannah Grace

Hannah’s father, who has been trying to break into the morgue to get her body back, explains to Megan he killed Hannah after her exorcism didn’t work and buried the body. Unfortunately, smothering Hannah might’ve killed her but it definitely didn’t kill the demon possessing her, which escaped the grave and is now using Hannah’s body as a host to kill people and gain more strength. According to Grainger, the only way the demon can be stopped is by destroying Hannah’s corpse.

After the possessed Hannah kills a few more people, including her dad, Megan manages to shove her body into the morgue incinerator which finally seems to get rid of the demon. However, the twist ending of The Possession Of Hannah Grace sees Megan getting on with her life but a blue flash in her eyes and a fly following her around suggests the demon has now taken possession of her. The lesson behind The Possession Of Hannah Grace? If you start an exorcism, make sure you finish it.

Next: I Am The Pretty Thing That Lives In The House Ending Explained