Batman Adventures #3
I just realized this new s_d is lacking in the Harley/Ivy fluff department. I shall remedy this.
During this time Arkham is, iirc, being rebuilt so when captured the regulars find themselves shipped off to Stonegate. At this point Ivy is going through some plant/body-related changes putting her on edge and doesn't realize Harley has also been locked up leading to a bit of a misunderstanding.
So Harley passes out and is shipped off to the infirmary while Ivy, well...
Harley and I.V. Heh. Despite being hurt, Harley manages to swoop in and save the day.