A black-out occurs during the meeting of a gang of criminals. When the light is back one of them is found killed with a stab on his back and all the clues point to a penniless man who had an argument with the victim a short time before the murder.
After graduating in correspondence detective, Riccardo Finzi arrives in Milan. The first case he deals with is the death of a young maid. Cockpit in a surreal yellow from a novel by Luciano Secchi.
Luciano Persichetti is hypersensitive and convinced that he has paranormal powers. Susanna, a parapsychology student with whom he is in love, tries to help him interpret the paranormal warning messages he is receiving. When Luciano turns out to be haunted by a mysterious killer who calls himself "The Guardian Angel", Susanna discovers that Luciano's paranormal powers are not real at all.
