The Polaris

The Polaris summary:

On a pitch-black night, corporate wage slave Qi Yan sees his first love — the one that had passed 10 years before. After quite a bit of pestering and persuasion, he finds himself forced into the miserable lifestyle of working during the day and investigating at the night. The topic of the investigation? Finding out who the culprit is. Can the top who had passed years before successfully manage to be resurrected?