In the 25th year of the Republic of China, Shen Ruoyan, the heir to the old Nanjing mansion, returned to China and discovered that his mansion was actually the secret contact point of the anti-Japanese intelligence station. The person in charge of the liaison station is the calm and reserved agent Lu Shiyan, who lurks in the mansion as a butler. In order to protect her family and country, Ruoyan chose to cooperate with Lu Shiyan. In the interplay of light and darkness in the mansion, the two cracked codes and passed on information. Their love quietly grew amidst danger and trust.
