| Director | Chong-sik Min |
|---|---|
| Country | North Korea |
Ryongsu, a worker at the blasting furnace, suggests a way to develop fire bricks with their own technology without relying on import, but the technicians at the plant ignore Ryongsu's suggestions. Ryongsu and his assistant Hyeyoung work day and night researching fire bricks. This upsets Ryongsu's Ryongyeon who is jealous of their relationship. Ryongsu sends a letter to Ryongyeon to clear the air, but the misunderstanding remains, due to her inability to read. Ryongyeon studies Hangul. Ryongsu's research is endangered by spies, and Ryongyeon appears and saves the day.