A scientist starts narrating his diary when the film begins. On planet Earth the near future faces over-population, people are divided into one group active only during the day, and another group active only at night, both of which are living in an artificial space called ′Metropoli′. Sarah, a female doctor in the day group, finds that her missing daughter has become an illegal citizen of the night group, but there′s no way for them to meet again. [By Day and By Night] is a sci-fi film from Mexico, which warns against the loss of humanity generated by the abuse of scientific technology. The gloomy color of ′Metropoli′ stresses the filmmaker′s critical mind while dramatically contrasted with an open landscape of nature where characters run across while escaping. He also reveals his hopes for family love, as well as essential human love unchanging no matter how scientific technology makes efforts to suppress and control them. This film doesn′t provide visually striking effects often saturated in Hollywood sci-fi films, but stands out with its unique style triggered by imagination based on a clear and concrete theme. Notably, it deserves credit in that it challenges against a high-cost genre film, only with moderate dialogue, minimalistic costumes and fresh ideas. A debut feature by a new Mexican director, which has world premiere here at PIFF. (RHEE Soue-won)