A series of chance occurrences leads Kirk Langstrom to relapse into his Man-Bat identity after marrying Francine Lee, and the Batman must capture him and restore him to normal. Commissioner Gordon’s friend Officer Jim McClean has been murdered, and the Commissioner has vowed to catch his friend’s killer. This prompts Barbara Gordon to do her own investigation as Batgirl.

Man-Bat returns for a rematch with Batman. Since his marriage to Francine, Kirk Langstrom has battled with himself not to experiment with the formula that made him Man-Bat ever again. However, temptation proves too great and once again Langstrom creates the serum that turns him into Man-Bat and he battles the Caped Crusader. Meanwhile, Francine discovers the emergency antidote in Langstrom's suit jacket. Eventually, she tricks him into taking the antidote and he returns to his human self once again.

When a policeman is killed in the line of duty, Commissioner Gordon vows to catch his killer. Batgirl is soon on the case and as she approaches the killers, she finds they have a hostage...Batgirl. In fact it is a female gang member dressed as Batgirl and the two switch places in order to save the girl's life. The fake Batgirl then tricks Commissioner Gordon into thinking she is on the trail of the killer. Meanwhile, the real Batgirl escapes her captors and heads for the police HQ. But will she get there before the police killers turn their fire of the Commissioner?

1. "Man-Bat Madness!" (Batman) written, penciled and inked by Frank Robbins.
2. "The Deadly Go-Between!" (Batgirl) written by Frank Robbins, penciled and inked by Don Heck.
3. "Rex-Circus Detective" "A Demand Classic" reprinted from The Adventures of Rex the Wonder Dog #3.
4. "The Case of the Gold Dust Death!" "A DC Extra" reprinted from Gang Busters #30.