Guardian tells how two brave men do their utmost to restore peace in a world where humans, a human-like species with super powers called “Dixing people” and animal mutants coexist. More and more Dixing people, who live in their own realm deep under the earth, escape to the human realm and raise a ruckus. The chief of the Special Investigation Unit Zhao Yun Lan (Bai Yu) and his team are in charge of investigating all crimes that don’t seem to have been commited by humans. Strangely, a series of cases all involve a biology professor called Shen Wei (Zhu Yi Long), albeit he is never an offender. Zhao Yun Lan becomes more and more curious about this mysterious professor who looks at him with a strange gaze. What he doesn’t know is that Shen Wei has already known him for ten thousand years.