Batman Adventures v1 #12

A notable comic issue that introduces the character of Harley Quinn! And it features one of Batgirl's best knockout and peril scenes.

Barbara Gordon dresses up as Batgirl for a costume party in search for a kidnapped girl. Batgirl discovers Harley Quinn and Poison Ivy holding the girl bound and gagged. A fight ensues, and Batgirl manages to daze Harley.

Batgirl rescues the girl and attempts to escape. She runs into Harley in the hall and has a gun pointed at her. Suddenly, a thug knocks out Harley with a blackjack. Batgirl is temporarily relieved, but is taken by surprise and knocked out herself!

Batgirl wakes up tied to a table, along with Ivy and Harley, and it turns out Catwoman is behind the whole scheme! The rest of the comic depicts how Batgirl escapes.