As a big big biggest fan of thriller-detective genre who watched almost every investigation kdrama, i really can spot a good one. Signal left me speechless, I was soo into this drama. It's so thriling with good plots and nice plot-twists. Also the cases are based on real crimes and incidents i know, so it's more interesting. This show is a roller-coaster with lots of moments you'll be shocked and amazed. Not every investigation-detective movies or dramas can leave you this immersed. Truly great!