After ensuring Gyeong-tae's safety, Su-yeol pulls a dirty move. With Kim Gye-sik back on the force, the narcotics unit tracks down a street drug.

Su-yeol searches high and low to prove Hui-gyeom's innocence. But the deeper he dives into the case, the closer he comes to falling into a trap.

Su-yeol's hunt for the truth endangers those around him. He has a final face-off with the crazed killer at the place where it all began.