Su Nian touches a broken jade bi of Kunlun Mountain, and travels through time to the Western Regions of the Tang Dynasty, where she is rescued by the garrison commander Bai Ze. The jade bi belongs to Yun Yao, who disappeared ten years ago. Yun Yao tells her in a dream that she is not reincarnated, but summoned back by the jade bi. The rift expands, and Bai Ze's spiritual power diminishes. The two go deep into the secret realm along the old path, discovering that Yun Yao left behind a path that was never walked through: instead of sealing the rift, it bypasses it. You Tong peeks in the dark, and the jade bi points to the unknown. How will Su Nian return to the future? The secrets Bai Ze hides are far more than what he has spoken. The two shoulder to shoulder step onto this millennium-unfinished path.