Nestor, 22, works the night shift as a receptionist in an industrial city in northern Mexico, near the border where he lives with her mother, Lilia. One day Nestor discovers a math problem, a problem that made him fail in the past. Lilia, 58, recently lost her job due to downsizing and is now looking for a way to move forward in life while facing old age. Nestor wants to leave, but being the youngest son and the only one still living with his mother, he finds it difficult to make the decision to leave her. Soon, the mother and the son come to a mutual understanding that they must separate themselves from the past so they can face their lives ahead.