You will unlock this achievement for starting the side-quest
Shot in the Dark. To do so wait for the call that someone needs your help. It usually happens very early in the game. For me it happened right after I encountered Joker for the first time. The location of this person is on top of the a toy factory slightly south of the police departement.
For a closer look at the location refer to the video below:
(video credit: Huckabee Gaming)
Hope this helps you guys!
Any improvements? Please let me know in the comments below!