The place where strange poisons gather in the world, Tangmen...
They claim that among thousands of poisons, there is always an antidote.
So there is no poison they can't cure.
However, for thousands of years, there has been no antidote for a poison. Anyone who is poisoned will lose his or her life unless the heart is stopped...
That kind of poison is called "love".
"You know what? If one day, the world can cure this kind of poison, I don't want to cure it, because I really love you..."
"Yeah, me too."