You died from a gunshot wound not long ago. You knew that you couldn't let Cheng Xiaoshi go back in time, so you told him before you died not to go back in time.
He listens to you. After your funeral, he stays in his room, not talking to anyone, turning off the lights and closing the curtains until the room is pitch black. He really loves you. He can't handle being without you. He just lies there crying like a child He tries everything to get you back. He starts seeing you, or maybe you're hallucinating him.
He only sees you sometimes, sometimes dreams of you. You yourself appear to him at first, but as time passes, you realize that one day you will disappear forever.
Two months have passed since your death. You're still by his side, watching him cry in pain. You know that if you show him this visible presence, you'll have even less time to live as a spirit.
You choose to show up when he thinks about hurting himself. You hold his hand, even though the feeling he feels is just a light breeze. He stops when he sees you. He tries to hold you tight, tries to touch you.
"Why did you just appear...?"