In Detective Conan's The Dark Chaser, Agasa Hiroshi was finally found to be behind the dark organization. What is the plot of that paragraph?

I only know that it was the 900th episode, because when he was a child, his father thought there was something wrong with Agasa Hiroshi, so he moved to the doctor's house next door. The reason why Agasa Hiroshi is the leader of the dark group is because Ali is Li Azhu, which means Maria in Latin, Sherlock Holmes' sworn enemy, and London No.2 suspect. That's all I know.