Mu mwaka wa 1981, umuryango wa Glatzel urahura n’ikibazo gikomeye: umwana w’imyaka umunani, David, arigarurirwa n’imyuka mibi. Abashakashatsi b’iby’imyuka, Ed na Lorraine Warren, barahaguruka ngo bafashe mu gikorwa cy’iyirukana ry’umupfumu (exorcism). Ariko ibintu bihinduka bikomeye ubwo Arne Johnson, umusore w’inshuti y’umuryango, yemera ko iyo myuka imwinjiramo kugira ngo ikuremo David.

Nyuma y’icyo gikorwa, Arne atangira kwitwara mu buryo budasanzwe — kugeza ubwo yica nyir’inzu yari acumbitsemo. Mu rukiko, Arne avuga ko yakoze ubwo bwicanyi ari mu maboko y’umupfumu. Ni bwo bwa mbere mu mateka y’Amerika umuntu yitwaje imyuka mibi nk’impamvu y’ubwicanyi.

Ed na Lorraine Warren batangira iperereza ryimbitse, rinyuze mu mateka y’imyuka, amasezerano y’umwijima, n’ibimenyetso by’ubuhanuzi. Uko bagenda babigenzura, niko basanga hari ikintu kinini kiri inyuma y’iyo myuka — ikintu cyashobora kuba cyarateguwe kera, kandi kigamije kurimbura abantu.