Cecilia is a sociology teacher. One night the son of her maid desperately knocks on the door of her house. She doesn't open. The next day, his body shows up murdered by the police. Cecilia begins to be haunted by the young man's ghost.

Cecilia is an academic teacher who lives alone with her son Juan, somewhere in Buenos Aires. One stormy night she wakes up scared by the knocks she hears at the door. She sees that it is Kevin, son of Nebe, the woman who helps her around the house. Cecilia, terrified, does not open, and hides in the dark, while she listens outside to the sirens of patrol vehicles. The next day, she learns from the news that the neighborhood where Nebe and Kevin live has mobilized to search for the young man. Neighbors accuse the Gendarmerie of being responsible for his disappearance, until he finally appears drowned in a river. The guilt that Cecilia feels and her inability to confess that the young man was knocking on the door of her house that night becomes too much for her. Kevin's "ghost" starts haunting her and following her all around.—exe_malaga93