Legendary Assassin Hornclaw (Lee Hye-Yeong) is now in her sixties, however she is still regarded as the best at taking out bugs as her former mentor Ryu (Kim Mu-Yeol) used to call society`s lowest of the low people. People that have escaped justice, just one of the uses for these assassins for hire that follow a strict moral code of honour even while taking out the scum of society. Rules that were written many years ago by Hornclaw and her mentor for all to follow at their agency. Guidelines that should be followed to the letter because if you don`t then most severe penance will follow at the hand of another assassin. Maybe it is due to Hornclaw`s age that she shows compassion for a doctor that helps her one night with her wounds, she starts to get to know both Doctor Kang (Yeon Woo- Jin) and his young daughter. Breaking the rule of no witnesses, plus her relationship with the Doctor sets her on a path to be taken out by her own agency, In turn also sets in motion a head to head with new liquidator Bullfight (Kim Sung-Cheol)and from within the agency someone has set this betrayal all in motion. Using Bullfight`s obsession with Hornclaw – The Godmother as she is known throughout the underworld. Bullfight knows her from the past, he will do anything to stab her in the back, but why?