Francine worked with her husband Kirk at the Gotham Zoo, studying the behavior of bats. Her father, Dr. March, had a strong belief that bats would be better survivors in the future than humans, and worked on a formula to create the potential new breed of dominant species, the Man-Bat.
When Kirk tested it on himself, he would frequently turn into a giant bat creature, and then back into a human. Francine and March tried to help him, but the formula had already taken control of Kirk, and he stole various pharmaceutical chemicals as the Man-Bat. It was not until the intervention of Batman was Kirk cured.
Later, Francine startled her father, who, unknown to her, was recreating the mutagen to intentionally begin the new Man-Bat race. Tired from working all night long, March accidentally dropped the beaker containing the mutagen, and it spilled all onto the floor. Francine helped clean it up, but a shared of glass cut her finger, and a small drop of the mutagen had entered her bloodstream, causing her to become the "She-Bat".
It wasn't long until She-Bat started appearing in Gotham and was reported to the authorities. However, unlike her husband, Francine could not remember turning into the creature, leading her to believe that he was taking the formula again. Already faced with the unpleasantness Kirk once caused as the Man-Bat, Francine decided to leave him. Kirk pleaded that he would never take the formula again, and that there could be the possibility Batman only administered an incomplete cure. Batman decided to check facts, but Francine would hear nothing of it, electing to leave town.
She boarded a plane out of Gotham, but Kirk had followed her, saying that Batman had proof that he was not the creature. Taken aback, Francine agreed to come home, but suddenly felt very strange. She ran to the washroom and saw herself transforming into She-Bat. In her feral state, she forced the plane door open and flew out. However, Kirk was knocked unconscious by the falling cabin pressure and he was sucked out, leading She-Bat to grab him as he fell.
She-Bat flew with Kirk to the Gotham Bridge Tower where she was confronted by Batman. After a very difficult fight, Batman managed to shoot She-Bat with the antidote, and Francine reverted to her human form. In a dazed state, she almost fell off the bridge, but Kirk had come around and caught her. The two embraced as he declared the nightmare was over.
- "Chemistry" (Cameo)