Qin Yi has an unknown secret, and he has some voice control.
It wasn't until the singing of "Morning and Night" cured his insomnia that he knew he couldn't live without her.
Xi Guan: Mr. Qin, even if you find out that "Morning and Night" is me, I still can't sing the song you gave me, because I... Have lost something I was once proud of.
Qin Yi: "Can such a thing be recovered?"
Xi Guan: "I can't get it back."
Qin Yi: "Then change something to make you proud?"
Xi Guan: "..."
Qin Yi: "What do you think of the title Mrs. Qin?"