"The birds hear the daytime words, and Seowoo hears the nighttime words." Seowoo (서우) lives in constant tension as a hidden information broker, selling secrets for a living. One day, Lee Jin (이진), an organizational operative with a 100% emotional, "F" type personality knocks on Seowoo's door. He seems suspicious... and clearly looks like he belongs to a rival organization... Yet, strangely, Seowoo finds that he connects with this person too easily, and his professional guard begins to drop. An uneasy and suspicious relationship begins between the 100% tense information broker and the 100% emotional "F" type operative (?). Is this feeling an elaborate plot, or true sincerity?