Heikinkatu, now Mannerheimintie, was the main traffic artery of Helsinki in the 1930s, "the street that would never be completed". Already in the 1930s, it became clear that Heikinkatu, due to its unfavorable cross-section, was unable to absorb the ever-increasing traffic. The film follows the renovation of Heikinkatu, which was eventually completed, thus providing a major thoroughfare to the capital.