Synopsis:

Italo-American Jack Altieri is called to the Umbrian village of Vesta to restore a painting of Medea di Carpi, a Tuscan noblewoman accused of witchcraft.
On his arrival he learns that a giri has been brutally murdered and inspector Gianzi suspects him of the crime.
He is put on his guard by lris, the owner of the pensione where he is staying, and Silvia, who says she is Countess Eloide Prinzivalle's sister and begs him not to complete the work on the picture.
When the local councillor for culture is killed before he can tell him of the prophecy regarding Medea, Jack realizes he has been caught in a trap. Eloide Prinzivalle denies having a sister.
lris is the only person to believe Jack innocent and she puts him in touch with Father Guelfi, who telIs him of the prophecy linked to the Medea portrait.
Medea is a deviI who will come back to life when the portrait is restored.
The only solution is to destroy the painting that is so important to the devil worship sect led by Eloide Prinzivalle.