Gu Yan’er came to Earth to find her master (Tang Xiu), only to realize that because of fighting with another immortal while escaping, her escape method deviated from the expected. Leading to teleporting before the arrival time of when Tang Xiu's soul returns to Earth. Establishes this restaurant to help when Tang Xiu comes back (I think that's what this is for).
On the outside, Everlasting Feast Hall may look like just a really high standard and luxurious restaurant for the rich people, but in secret, it's supposed to be a place where the cultivators taught by Gu Yan’er stay at. Managing the place while she waits for her masters return to get rid of the poison given by Zhu Wushou’s (Bad guy in the immortal world) Twilight Nightmare.