Can somebody help me find a xicheng fanfic?

Okay, so I have been looking for this fanfic for weeks now and I saw it one time then lost it out of nowhere. The summary is that it was a few chapters long and it was xicheng fanfic, yet instead of Yiling Laozu Wei Wuxian- it was Yiling Laozu Lan Xichen instead. It looked REALLY GOOD and I am SUFFERING HERE, HELP PLEASE..