```html
By the time Gu An returned to the Third Medicine Valley, it was dusk. He called upon An Xin to accompany him back to his pavilion.
"Master, is there something you need?" An Xin asked curiously.
Gu An rarely called her proactively; whenever he did, it was certainly about something significant.
Gu An smiled and asked, "If I were preparing to leave, what would you think?"
Upon hearing this, An Xin's face instantly turned serious. She knew her master wasn't joking, because over the years, she too had sensed that something was off.
The world widely propagated the concept of the Heavenly Dao, and everyone was expected to believe in it and pursue the Celestial Mandate. Initially, she didn't feel much, but when she heard disciples say that the world's destiny was predetermined by Heaven, she realized something was amiss.
She still remembered He Qingsong's words: the Heavenly Dao did not want her master to interfere.