Fan Chen, a simple boy with a puppy face, is actually the most feared professional killer in the underground world. He kills people without knowing he is cruel, just because "the mission is the mission." One day, he accepted a mission to assassinate the evil superpower "Dark Emperor", but was trapped by the Dark Emperor using the evil superpower "Soul Cage" and became a stand-in puppet - the Dark Emperor needed to borrow Fan Chen's pure body to avoid pursuit.
When he was about to die, Fan Chen activated the "Lottery System" and could obtain random abilities with each lottery. However, the system has a weird setting: all the abilities drawn are related to "substitutes" - substitute phantom, damage transfer, identity copy... He must use these substitute abilities to deal with the control of the Dark Emperor while finding a way to release the soul prison.
As the lottery progresses, Fan Chen discovers that the Dark Emperor's true purpose is far more than just a substitute - there is a conspiracy to destroy the world behind his evil powers. And Fan Chen, this seemingly innocent dog killer, will tear apart all darkness in the purest way.
