Thirteen-year-old Michel is vacationing in a secluded Acapulco beach bungalow with his recently widowed mother, Elena (Sasha Montenegro), and his younger brother. Having taken on the role of the "man of the house" since his father's passing, Michel is fiercely protective and increasingly, uncomfortably possessive of his mother. When Elena meets and begins a serious romance with a handsome architect named Carlos (José Alonso), Michel's deep-seated Oedipal complex is violently triggered. Determined to be the only man in his mother's life, the troubled teenager embarks on a vicious, erratic campaign of terror against Carlos to eliminate the competition, culminating in a brutal, blood-soaked finale.