Satanik is a Spanish-Italian co-production that tells a story about Dr. Marnie Bannister, a scientist horrifically scarred from her past. In a lab in Madrid where she works, a colleague has successfully created a substance able to regenerate cells. However, the animals he experiments on become aggressive and dangerous. Dr. Bannister wants to be the guinea pig in the trial, but they refuse her. Therefore, she kills for the substance, takes it, and transforms into a beautiful young woman... and also a vicious killer who will go to great lengths to keep her secret.