Why did Detective Liu Qingyun see He Jiaan's little boy?

Because detective Chen Guibin, played by Liu Qingyun, can see the "ghost" in people's hearts, and the cowardice in He Jiaan's character is gradually amplified, resulting in a little boy, so Chen Guibin can see it.

Chen Guibin solved countless cases, but he was called a madman by everyone. He has a specialty-seeing the split personality in people's hearts, that is, seeing ghosts in people's hearts. His ability makes him a lonely man. However, Inspector He Jiaan of the Major Crimes Unit turned to his idol "Detective" Chen Guibin for help because of the difficulty in solving the case.

In the process of solving the case, Chen Guibin's unique way of solving the case and the cunning of the real murderer Gao Zhiwei made He Jiaan reject Chen Guibin and devote himself to Gao Zhiwei's hypocrisy. At the end of the film, Chen Guibin killed Gao Zhiwei to protect He Jiaan, but although he successfully killed Gao Zhiwei, he died in He Jiaan's "cowardly" and "insidious" character.

Chen Guibin can see that there are ghosts in people's hearts, which makes him a "madman". He pursued perfection, and when he resigned, he cut off his ear and gave it to the director who had no ghost in his heart. He urgently helped He Jiaan, who was "weak" in character, and fought Gao Zhiwei, who had seven ghosts in his heart, at all costs. He died at the hands of those bad things after all. Kindness can't survive in this land, which is the biggest emotion that the film gives the audience.

He Jiaan is a policeman. He looks tough, but his inner ghost is "weakness". After solving the case, he took a neutron bomb and watched Chen Guibin slowly die under his own gun. His fear gave birth to "cunning"

At the end of the film, there are nearly two minutes to watch He Jiaan rearrange the murder scene from a overlooking angle to get rid of the responsibility. A just policeman finally left his name on the devil list.