I’ve taken a big break from dramas and started watching this recently on a whim. I had already watched a couple episodes in the past but dropped it because i felt the cold case plot in the first couple episodes was very simplistic and one dimensional. That Is the criticism I give of this drama. The smaller cold case sub plots are not great. The villains are very one dimensional and just frustratingly unbelievable. The police corruption moral plot line is very heavy handed. But if you get past this, the overarching time travel plot and relationships among the main characters is very strong. It keeps you guessing and emotionally invested. So it’s not perfect but an entertaining watch after things get moving.