Mine Alone

First we hear then we see, in black and white, an argument between a man and woman. In a series of flashbacks in color, we see them meet, marry, and expect a child soon after. He turns abusive: he's Joaquín, an ad executive with a temper; she's Angela, a receptionist when they meet. The relationship unravels as each incident is more damaging. Angela's friend and confident is the wife of Joaquín's boss, so their problems spill into his work. He refuses to seek help. As he gets more threatening, the law does little. Is one or the other's death the only way this can end? And the flashbacks, where do they originate?