After Falling Asleep, I Learned to Walk Through the Side Door

Zhang Zhijie, a promising young man from modern times, can travel into the past in his sleep. There, there is a Taoist who gazes across the sea with a single thought, and there is a singer who dances like a dragon and stabs the immortal. But under that, there is more of a world where "the heart is worried and the weather is cold".