How did Julian learn of the plot to embarrass Ginger and Nadia?

Julian learned of the plot to embarrass Ginger and Nadia through a conversation he overheard between two classmates who were discussing their plans. They casually mentioned specific details about the scheme, which piqued his interest. Concerned about the potential fallout for Ginger and Nadia, Julian decided he needed to intervene and protect them from the humiliation.