Fighting gangs

Li says several officials from the law enforcement authorities had closely guided them from the beginning of scriptwriting to the actual shooting, giving the crew professional suggestions to ensure that all the details－from legal terms to titles－are accurate and convincing.

Wu says he learned a lot by watching video recordings of the monthslong trial of an official charged with corruption.

"In the first week, his hair was mostly black with just a small bunch being gray. But his hair turned completely gray three months later because of the huge stress. I was very shocked to see this change. I wrote this detail for one character in the series," says Wu.

In an attempt to help actors get deep into the characters they are playing, some cast members were arranged to stay with police officers to gain more firsthand information. For instance, actress Wu Yue studied how to act like a real-life senior police officer by staying with a female deputy director of a public security bureau.

Wu Bai, the director, says he also used close-up shots and special photography techniques to capture the nuanced emotional changes in the faces of characters, and intentionally left some unsolved riddles for the audience to figure out what the truth is.

"For example, one of the most discussed mysteries is who is the biological father of Sun Xing (the top villain in the series). Interestingly, we changed the idea multiple times during the creation procedure. For us, it was also like a puzzle-solving journey while writing the script," says Wu Bai about his formula to attract a curious audience.

The series has also got attention overseas, with some foreign audiences asking for English subtitles on fans-aggregating base Mydramalist that fans of Asian dramas and movies use.