Our protagonist is a young man named Fenix once Fenix the Boy Magician, of the Circo del Gringo. His father, Orgo, runs the circus and is nominally a knife-thrower, although most of his time seems to be dedicated to drinking and abusing his family. His mother, Concha, is the queen of the flying trapeze as well as a devotee of the Santa Sangre Church, where she and her followers worship a girl whose arms were cut off by rapists. The arrival of a Tattooed Woman and her protégée, the deaf-mute Alma, sparks a chain of jealousy and lust that culminates in gruesome death, all of it witnessed by Fenix firsthand.
So deeply is Fenix traumatized by these events that by the time the film opens, he, now a young man, is confined to a mental institution. He doesn't speak; he doesn't eat normal food; and he seems entirely convinced that he's actually an eagle. One night, he and some of the other patients are taken out on a a field trip into the city. It's during this adventure that Fenix happens to see someone he hasn't seen in years not since that last night at the circus. The sight of her shocks Fenix out of his stupor once more, and although his sanity is still in tatters, he finally has a purpose... even if that purpose is not entirely his own.
Santa Sangre contains examples of:
- Abusive Parents: Orgo, Fenix's father, is a philandering, abusive drunk who, it is implied, was kicked out of the United States for allegedly murdering a woman there. He even carves a tattoo on Fenix when he's merely a child to "make him a man." Concha, Fenix's mother, is worse, being a former member of a blaspheme cult, mutilating Orgo and driving him to suicide, and manipulating Fenix emotionally into killing any woman who dares get close to him. Not to mention that her love for him has a NASTY incestuous tone. Subverted in Concha's case: she was Dead All Along.
- Amazonian Beauty: The Saint. And Fenix is clearly into it.
- An Arm and a Leg: Concha and the other followers at the Santa Sangre church worship a "saint" who was martyred when the men who were raping her, tired of her struggling, cut off her arms. Ironically, Concha later meets a similar fate.
- Animal Motifs: Birds. Such as Fenix's name, the phoenix tattoo he and Orgo both have, and the roosters and swans he hallucinates. Also he believes himself to be an eagle in the first scene of the film, which transitions to a shot of a real eagle flying over the city.
- Bittersweet Ending: Fenix is reunited with Alma and, with her help, seems cured of his madness... which leaves him feeling downright chipper as he walks outside, covered in blood, and straight into the police, who are about five seconds away from discovering all the women Fenix has murdered on Concha's behalf. Yay?
- Children Are Innocent: At least compared with the cruel adults.
- Cute Mute: Alma, a trapeze artist who was one of Fenix's friends at the circus, and who later helps him out in adulthood.
- Evil Redhead: The tattooed lady. She tries to pimp Alma after she has become a prostitute.
- Fat Bastard: Orgo. Also that fat prostitute thing.
- Gainax Ending: Fenix and Alma use The Power of Love to overcome Concha's hypnosis and kill her, only for her to tell Fenix he will never be rid of her. She then disappears, and it is soon revealed that Concha was killed when her arms were cut off...
- Groin Attack: Concha retaliates on her cheating husband by pouring acid on his groin.
- Harmful to Minors: Fenix witnesses his father having brutal sex with his mother, then the death of an elephant, and later his father wandering out of a building, naked and bleeding from the groin, and stabbing himself. Not to mention the tattoo...
- Important Haircut: Fenix goes from unkempt long hair to a subtler ponytail once he's under Concha's control.
- Incest Subtext: Fenix's relationship with Concha after her return is loaded with this.
- Jumping Off the Slippery Slope: Concha may have been justified in killing her first victim, but all the others simply made the mistake of flirting with Fenix.
- The Living Dead: As Alma weeps over the Tattooed Woman's corpse, said corpse's stomach can be plainly seen moving up and down with breath.
- Meaningful Name: Fenix is obviously a phoenix. Alma means Soul in Spanish. Orgo sounds like orgasm. And Concha is vaginal slang. (And let's be honest, Concha is a total cunt).
- Momma's Boy: Fenix, who shows affection for both his parents as a child but becomes totally devoted to Concha as an adult, while never sparing Orgo a thought.
- Monster Misogyny: All of Concha's victims are females, mostly ones who lust after Fenix. The only exception is Fenix's father.
- Primal Scene: Fenix witnesses a particularly devastating one that intercut with an elephant dying.
- Psychological Horror: The film is about Concha's descent into insanity and the (partial) redemption thereof.
- Rule of Symbolism: There's a plenty of valid symbols (blood, missing arms, The Invisible Man).
- Something Else Also Rises: Fenix and a giant python bring us perhaps the most over-the-top visual metaphor in the history of film.
- Twist Ending: Concha has been Dead All Along, her appearances having been another instance of her unstable son's hallucinations.