Three years ago, a wrong judgment caused the star police detective Hua Qiangu to fall from the clouds and be ruined. Now, she is hiding in the noisiest corner of the city, running a private detective agency that only accepts "trivial cases", numbing herself with alcohol and boring cases. However, a bizarre "secret room" murder broke her rotten peace. The deceased was a giant in the biotechnology world, and the only clue left at the scene was a cold mechanical cicada. The secret request from her former mentor drags Hua Qiangu back into the abyss she swore she would never step into. As the investigation deepens, she discovers that this is not an isolated murder, but the prelude to a huge conspiracy sweeping the entire city. When friendship faces betrayal, when courage is eroded by the nightmares of the past, Hua Qiangu must stand up again in the ruins, face the "echo" that pushes her into the abyss, and prevent it from swallowing everyone's future.
