The blue-and-white jade token his father left behind takes him through thirteen worlds.
The first world: Meet Yourself.
He squats by a construction site wall with an unlit cigarette between his lips, stopping Xu Hongdou, a manager at a five-star hotel. "Your friend Chen Nanxing has a blocked pancreas. She can still be saved now. In another two or three months, even the gods won't be able to help."
Xu Hongdou calls him crazy.
Later, the diagnosis comes back: a precancerous lesion.
He says she doesn't need surgery; he can cure her. His condition is outrageous: "Once she's healed, both of you are coming with me."
Three months later, the lesion is completely gone. They spend half a lifetime together in gentle devotion, from Yanjing to a breezy little town, from hauling cement to opening a chain of congee shops, from saving one person to bringing an entire world to a happy ending.
He doesn't seek domination, bloodshed, or to force anyone's hand. He just can't stand seeing regrets. He wants to live well, love well, and enjoy an ordinary life.
Poison, the protagonist's skills and so on were just given to his adoptive brother for free.