Yan Lin will never forget what Xiao Lie said. He said: "I will use hatred to lock your footsteps, use love to trap your body, and use my life to let you stay. You can only belong to me!"
If there really is a red thread in this world, then what Yue Lao tied to him and Xiao Lie was a lock without a key. It was obviously inappropriate and there was no key to unlock it.