Injustice: Gods Among Us #5

Green Arrow captures Harley Quinn to keep her safe from Superman. In his car, Green Arrow hands her an arrow that sprays her with sleeping gas, putting Quinn under for the rest of the trip.
Later, the gas wears off and Harley awakens in the Arrowcave. She mocks the lair's name and mentions that the Joker used to drug her and leave her in lairs regularly.