Detective Comics Vol 1 #429 CGC 7.5

An underground nuclear test in New Mexico sends shockwaves as far as Nevada, disrupting warrens occupied by swarms of vampire bats. The panic-stricken animals take to the air and descend atop Hoover Dam and the Las Vegas strip. Outside of a Vegas casino, a man is found dead in an alley. His skin is pale and he has two puncture wounds on his neck.

In Gotham City, Bruce Wayne and Alfred monitor televised recordings of the bat phenomena and learn that Doctor Kirk Langstrom and his wife Francine have been called in to analyze the situation. Bruce suspects that Langstrom might be up to no good and decides to travel out west.

Sometime later, Batman conspires with a show girl named Debbie, former girlfriend of the "vampire" victim, Jim. Debbie agrees to act as bait for the Man-Bat. As suspected, the Man-Bat appears in the sky and swoops down on top of Debbie. Batman deflects the creature's attack with a batarang and the two combatants trade blows. The Man-Bat kicks Batman from the roof of the building and he is forced to slow his descent by desperately clutching at neon lights running laterally down the side of the building. He lands on the rooftop of an adjacent building. The Man-Bat pounces on top of him, but Batman turns the beast over, plunging it through a skylight onto the casino floor below. At this point, the Man-Bat decides to flee and flies off into the night. Batman commandeers a police helicopter and pursues it.

Batman flies the helicopter to Kirk Langstrom's base camp only to find the doctor resting peacefully inside his tent. He now realizes that it is not Langstrom who has become the Man-Bat, but rather, his wife Francine.

Batman and Langstrom go spelunking in one of the nearby caves where the Langstroms have been conducting their research. They find the She-Bat and Batman ensnares her with his Batrope. Francine is subdued and Batman decides that the only recourse left to them is to give Francine a full blood transfusion.