When the Lamp Burns Low, Another Night Passes

The title comes from Nalan Rongruo's poem "Gathering Mulberry Blossoms":

Who has turned to that mournful tune from the Music Bureau? The wind sighs, the rain sighs, the lamp burns low, and another night slips by.

I don't know what keeps weighing on my heart. Awake, I am restless; drunk, I am restless. Even in dreams, I never reach the Xie Bridge.

Premise: