The "May Day Slogan" was released on April 30, 1948, which attracted attention from all walks of life and responded actively.In order to prevent the founding of New China, the Kuomintang brutally suppressed progressive youth and assassinated patriotic democrats. A bloody storm was spreading in southern China.Senior intellectuals living in Hong Kong, led by the internationally renowned chemist Professor Tong Jiangnan, including experts, scholars and scientists, naturally became a thorn in the side of the Secret Service agents.In order to completely smash the enemy's conspiracy, we sent people to Hong Kong to secretly carry out the mission code-named “Beidou Operation” to ensure the safety of these people heading north to the liberated areas.On January 9, 1949, Tong Jiangnan's research results achieved a major breakthrough. People from all walks of life came to congratulate him, including many comrades who were preparing to go north.

That night, Ta Kung Pao deputy editor-in-chief Tu Zhe was killed. The secret agent Fatty met the newsboy Xiazai on the stairs, but he looked at him fiercely and hurried downstairs.Xiazai knocked on Tu Zhe's door, but when there was no response, he left without noticing the blood dripping from the crack in the door.The next day, Su Xing disembarked from the ship at the Hong Kong pier and happened to encounter several gang thugs bullying Shrimp Boy.Su Xing acted righteously, using kindness and force on the thugs to rescue Xiazai, but Xiazai disappeared in the blink of an eye.Tu Zhe, who was originally responsible for contacting Tong Jiangnan, was killed. A man named Luo Guanying came to Tong's house and claimed to be entrusted by Tu Zhe to come to the rescue. He also said that when ten o'clock arrived, Tong Jiangnan could call Tu Zhe to confirm his identity.On the other side, police detective Li Wenbo was searching the crime scene and suddenly received a call from Tong Jiangnan, who truthfully informed him of Tu Zhe's death.

Tong Jiangnan was shocked and sad when he heard this. He recalled his last meeting with Tu Zhe. Tu Zhe once revealed that Li Jishen's departure from Hong Kong had angered the Kuomintang and reminded him to be careful about his own safety to avoid being killed.For Tong Jiangnan, the death of his old friend Tu Zhe was like a bolt from the blue. The joy that Luo Guanying brought to Tong Jiangnan was wiped out by this news.However, Tu Zhe was killed when he needed to prove his identity to Luo Guanying. It was so strange that Tong Jiangnan became suspicious of Luo Guanying's identity. At the same time, he realized that he might have been targeted by agents of the Secrecy Bureau, and the crisis quietly came.After Luo Guanying left the Tong family, he went to Changhe Trading Company in person, and was held to the back of the head with a gun in the manager's office, while secret codes were exchanged.It turns out that Luo Guanying was not entrusted by Tu Zhe, let alone a human being. His true identity is the special commissioner of the Lieutenant Colonel of the Secrecy Bureau. In order to stabilize the situation in Hong Kong, Luo Guanying specially conveyed the “Bee Plan” to the leader of the operation Dang Xunqi in order to block it.Pro-communist elements travel north.

On the other hand, Su Xing successfully contacted Zhou Yaming, a party comrade at Qiming Bookstore. Zhou Yaming briefly explained the situation in Hong Kong. After discussion, the two decided to split up: on the one hand, Zhou Yaming reported to his superiors and re-established contact with Professor Tong; on the other hand, SuXing disguised himself as a postman and went to Tong Jiangnan's house to identify himself.Tong Jiangnan called Assistant Director Yinghua to ask about the cause of Tu Zhe's death, but the other party failed to give a clear answer.Since Tong Jiangnan had just been awarded the title of baronet by the King of England, and Tu Zhe was his close friend, the British side attached great importance to the case, and Yinghua even asked Li Wenbo to handle the case well.During the investigation, Li Wenbo discovered that Tu Zhe had received threatening letters before his death, and speculated that he had most likely offended someone important.

Dang Xunqi sent A Biao and others to monitor Tong Jiangnan's residence, but the person in charge was distracted by looking at women and failed to discover Su Xing, who was disguised as a postman.Although Su Xing was Tong Jiangnan's student and stated his purpose of coming, Tong Jiangnan was confused and disturbed by the appearance of two people claiming to be Tong Jiangnan on the same day, and eventually turned Su Xing away.Su Xing felt sad and confused about Tong Jiangnan's decisive attitude, which once again stirred up the scar in his heart, and realized that it would become more difficult to gain the teacher's trust.After returning to the contact station, Su Xing sat alone at the table in silence, carefully recalling the details of his meeting with Tong Jiangnan, suspecting that the teacher might have concealed some important information.