If this mini-series were a Beatles song, it would be "Everybody's Got Something to Hide 'Cept for Me and My Monkey."
This reminds me of "Macbeth," in that everybody's guilty of something and/or cynical or too self-absorbed to realize their actions are criminal. One of the least blame-worthy characters even commits a crime to protect someone she thinks is innocent, and she does not think she's a good person.
This uses a lot of fragmentation of time to tell the story of two violent crimes in a non-linear way. If you don't know Korean*, some of the nuance may be lost in translation and result in confusion, but there's a great degree of intrinsic confusion to the narrative, I think it's worth watching several times just to see where I missed clues the time before, and also because it's a lovely bit of storytelling.
The lead character, tough, whip smart Miss Lee (the "She" in the Englist title, and "Miss Lee" in the Korean title), is played by Kang Sung-Yeon. The last thing i saw her in, she played an insufferably virtuous damsel in distress, and that character really got on my nerves, so it was refreshing to see her play a well fleshed out complicated human being. All the characters are that well written.
*I don't *know* Korean, but I've picked up enough to recognize words like "bro (hyung)" and "sis (unni)" which can indicate literal older sibling of yhe same sex or pal whom the speaker regards as an older sibling. Neither one is translated as bro or sis in the English subtitles, but as "you" or the person's name, thus depriving a non-Korean speaker of some clues.