What is the relationship between Akai Shuuichi and Lu Yuan in Conan? Why did he say at 345 that he couldn't meet him for a drink?

Haiyuan Ai is the sister of Akai Shuuichi's girlfriend Miyano Akemi. She can't meet Haiyuan Ai because she needs to protect her secretly.

Related introduction:

Five years ago, Akai Shuuichi had long black hair. In order to secretly investigate the black organization's alias "Zhuxingda", he pretended to be hit by a car driven by Miyano Akemi, a member of the organization, and got to know Minmei, and used this interpersonal relationship to get to know Miyano Shiho, a scientist with a top brain in her sister's organization (organization code is Shirley, alias Haiyuan Ai after leaving the organization).

Later, Akai Shuuichi appeared as Okiya Subaru, secretly protecting Haiyuan Ai, and learned Conan's true identity.

Extended data

Miyano Shiho's former member of the black organization, code-named "Shirley", is a female scientist and the manufacturer of the drug APTX4869 which makes Kudou Shinichi's body shrink. He is very intelligent, favored by the organization and sent to study in the United States. After her sister Miyano Akemi was assassinated by the organization, she was dissatisfied with the organization's failure to explain it, and stopped drug research and development to protest.

Later, he was imprisoned by division. After taking APTX4869 to commit suicide, the body shrinks into a pupil. After betraying the organization, he was taken in by Agasa Hiroshi, alias Haibara Ai.

In TV926, Agasa Hiroshi said to Okiya Subaru: "In fact, she is just a girl of 18 years old at heart." Chongya replied, "She has always been a little girl, which helps a lot." This confirmed that Okiya Subaru/Akai Shuuichi knew that Haibara Ai's real identity was Miyano Shiho.