I watch this drama now 2024 .
The ML is the sparrow code name 23 undercover communist spy . He works for the puppet government under the Japanese. His jobs is to remove anti-Japanese fighter that on the surface. His main mission is to recover the code from the puppet government which could destroy china.
The ML friend is the leader of organization he work for. Chen shen saved him during the sino Japanese war , since then his boss consider him as a blood brother. The boss wife treat him as their family member.

The FL is Chen shen EX boyfriend and her former teacher. She work for the nationalist party KMT , she and her husband joined the organization. Their main mission is to get top secret and assassinate the traitor who work for the Japanese including ML boss , ML and FL uncle who is the top boss.

The second FL is Lin Xiao nan she love the ML Chen shen, he doesn't love her he consider her has his friend. On the surface she work as extra heroine in the film company later in the drama it reveal she is the doctor code name and Chen shen handlar. Later in the drama she get caught and her code name is doctor a Communist spy.

Her role is very annoying chasing after Chen shen asking him to be her boyfriend. Telling everyone one that he is her boyfriend. Mind you men doesn't like to be controlled. She even forbid him to talk to other women. They was one scene where she catch him and drag him out , he said to her you can't hold the sand similarly you can't force a man to like you.

Don't know why woman can steep so low, she even know that Chen shen doesn't love her because Chen shen gave his heart to Xu Bi Cheng. She keeps on forcing him to marry her.

Second FL also fall in love with the FL, he also know that the FL loved Chen shen alot she is willing to sacrifice her life to save the ML.
The second male lead get caught and he died.

The main Villian is Sun Xian ming he is jealous of Chen shen because Lin Xiao nan love Chen shen, he try many times to kill him by setting up traps and to prove to his supervisor than Chen shen is the sparrow. He is psychopath and he use extreme way to torture the political prisoner. In the end he also died a terrible death.

In the end Chen shen was able to retrieve the Japanese military code , his boss come to know that he is the sparrow and shot him at point blank range, his boss wife try to save Chen shen. He managed to escape but was followed by the FL uncle and he was blocked and was unable to escape. In the end Xu Bi Cheng help Chen shen to escape, Chen shen fake his death making the enemy think that he died. Xu Bi Cheng was saved by Mr Dao her compatriot, she think that Chen shen died in the explosion.

Xu Bi Cheng change side she became a Communist spy under cover she remain in Shanghai. Only few people know about it. Lesser people knew about her mission .

The drama fast forward after Japanese was defeated , Chen shen return to Shanghai and start to recruit new communist spy . She resemblance her sister in law. In the end Xu Bi Cheng saved Chen shen again.