Binhai detective Guo reopens a cold case and uncovers a secret. A mysterious rival hinders the investigation by obtaining evidence first. Ex-detective Wu Yu, fired in 2000, chases suspects globally to find the perpetrator.

In 2019, Guo Weijie, a newcomer to the Binhai City National Security Bureau, accidentally came into contact with an old case. After investigation, he discovered that there was a hidden secret behind the case. He has since embarked on a journey to find out the truth. But during the investigation, there is always someone who gets the clues before him. Who is this person? 19 years ago, Wu Yu from the Investigation Section caused casualties to a criminal suspect and was fired from his job. He has no reinforcements and no identity. With only his stubbornness and obsession, he travels all over the world and clings to various targets, just to find the real culprit. What will be the result?