There are only eight episodes of One Day starring Kim Soo Hyun and Che Chengyuan. The ending subverts the contents of the first seven episodes and tells the audience who killed Kim Soo Hyun in an understatement.
The real killer of Hong Juhua is the clinic doctor who prescribed her medicine before. This case is a love murder. The description of the real murderer in the play only uses one photo and one sentence. As for the doctor's criminal process, there is no description.
As for the result, how did Chrysanthemum kill him, what did he do, why did he do it, and why did he do it. It doesn't matter, because drama is used for satire and accusation. Except for criminal defense lawyers, even Xianxiu doesn't care who the murderer is.
There are no lines in the last ten minutes of the ending. Hyeon soo Kim walks on the streets of the city, sits on the bus and stands on the roof of the city center. Wearing the most ordinary casual clothes, it seems out of place. Hyeon soo Kim, who learned to smoke, stood on the roof, looking at the bright night view of the city, feeling all kinds of flavors in his heart, but without any emotion.