Set in a rural Mexican community, La India (Isela Vega) lives with her young son, El Potro. She maintains a passionate, ongoing physical relationship with "El Zarco" (Mario Almada), a local violent enforcer who is also her son's unacknowledged biological father. Traumatized after witnessing his mother engaged in sex with El Zarco, the young boy shoots at them in a fit of rage and becomes consumed by intense erotic nightmares and complex fixations surrounding his mother. As El Potro grows into a young man, his obsessive resentment toward El Zarco intensifies into direct rivalry for his mother's presence and affections, culminating in a tragic spiral of violence.