Do you know that there are mysteries on both sides of this issue? What do you mean?

This sentence describes that there are some mysteries hidden in a certain situation or thing. Among them, "Tao Tan" refers to wisdom words or riddles similar to Taoist philosophy. And "there are mysteries on both sides of March 4th" is to describe the situation or things at that time with some far-reaching details or connotations. What does it mean may need to be explained according to the context or specific circumstances.