- Directors: Dario Argento
- Producers: Salvatore Argento
- Writers: Dario Argento, Bernardino Zapponi
- Genres: Horror, Mystery, Thriller
- Actors: David Hemmings, Daria Nicolodi, Gabriele Lavia, Macha Meril, Eros Pagni, Giuliana Calandra, Glauco Mauri, Clara Calamai, Piero Mazzinghi
Profondo Rosso follows music teacher Marcus Daly (Hemmings) as he investigates the violent murder of psychic medium Helga Ulmann (Macha Meril), which he witnesses in an apartment building. Other key characters are introduced early, including Dalyâ€™s occasional friend Carlo (Gabriele Lavia), Ulmannâ€™s associate Dr. Giordani (Glauco Mauri) and reporter Gianna Brezzi, with whom Daly begins an affair. Brezziâ€™s character is played by Daria Nicolodi, who would later become Argentoâ€™s partner and the mother of his daughter Asia.
In his failed attempt at rescuing the medium, Daly realises he could have seen the killerâ€™s face among a group of portraits on the wall of the victimâ€™s apartment but is unable to find or recognise it when the police arrive. Later in the film, he also initially overlooks another clue that leads him to discover a mouldering corpse walled up in a derelict house. In typical Argento fashion, one murder leads to a string of others as Dalyâ€™s obsession with this vital clue that he fails to understand puts his life and those of everyone he comes into contact with in danger. This inability of a character to interpret or comprehend what he has seen is a common theme in Argentoâ€™s films and was used repeatedly in Tenebrae.
Profondo Rosso is laden with minor details that presage later events. The bathtub murder is foreshadowed by an earlier scene when Daly is lightly scalded by an espresso machine; similarly, Daly explains to Gianni that his psychiatrist once explained that his piano playing is symbolic of him bashing his fatherâ€™s teeth in, and later in the film Giordani suffers exactly that fate. A childâ€™s doll hanging from a noose and a brief cut to a dog fight (with one dog biting the other by the neck, the other carrying a strange, ghastly gaze) foretell Marthaâ€™s aforementioned demise at the end of the film, when the heavy neckchain she is wearing becomes entangled in the bars of an elevator that then ascends, lifting her into the air until she is decapitated. The film also marks the introduction of many of Argento’s key hallmarks: discordant soundtracks, odd angles, rolling cameras and various lighting techniques.