( After Arkham Knight - Before SSKTJL )

After Joker's death she was vangeful against Batman and his Sidekicks, her whole purpose became about kiling Batman and its loved ones. To be succsessful Harley started doing plans, gathering man power and guns. Troughout the Scarecrow's attack on Gotham Harley and her man was waiting for the right moment. She attacked and failed, the rage inside her was killing her inside out. And than it happened.. When Batman's identity revealed to whole world like all the other people she was shocked too not so much after Bruce ( Batman ) blew her mansion and dissapeared.

Harley was a criminal there is no changing that and but even she knew without Batman and a protector streets will be flooded with criminals like her maybe even worse. From sheer respect and idea of controling Gotham's villians she created a gang called "The Quinnspiracy" and started to protect Gotham's street to her liking.