Assassin 606 (Saeyoung x Reader)

You are known as an Assassin number 606. You have a dark past. What is it you may ask well you have to read to find out. You are assigned a recent kill order for an Agent named 707. What will you do when you realize this agent is a person from your past. Will that stop you from your task?

fanfic I do not own the rights to any of these characters