Carl Kruger was a former mental patient, the inventor of the "death ray", and the leader of a militant group of scientists known as the Scarlet Horde that were obligated to rule the world.
Kruger attacked New York City prompting Batman to try and bring the terrorist to justice by attacking Kruger in his home and follow him to his base of operations. Kruger captured Batman, however the Dark Knight avoided execution by switching places with a guard whom Kruger blasted his death ray on.
After escaping the compound, Batman flew the Batplane at Kruger's dirigible in a suicide run. The two collided and exploded, however Batman was able to parachute away just before the collision. Kruger went after Batman and the Caped Crusader managed to get on the wing of plane and knock Kruger out with a gas pellet. Kruger then lost control of his plane and crashed into the water. Kruger's body was later recovered and it was indicated he died.