The Joker and the Penguin team up on a crime wave based on signs of the zodiac. The pair, aided and abetted by a woman known as Venus, keep Batman and Robin on the run. The Dynamic Duo manage to capture the Penguin but the Joker remains on the loose. Batman and Robin figure the Joker's next caper will take place at a museum and lay a trap. But the heroes are captured instead. Now, Batman and Robin face almost certain death; the heroes are to be crushed beneath a giant asteroid on display at the museum.

Batman and Robin narrowly escape the Joker's death trap and quickly get back on the villain's trail. The villain runs the Gothham City Police Department ragged with his crimes based on the zodiac. Meanwhile, Venus, the Joker's accomplice, warms to Batman. Eventually, the Dynamic Duo again corner the Joker. But, once more, the heroes are captured. Now, Batman, Robin and Venus are chained in a shallow pool with a giant clam. The clam swallows Robin and Batman and Venus will be next on its menu.

Batman, summoning all the strength he can muster, breaks his chains and frees Robin from the giant clam. The heroes arrange for the Joker's former confederate, Venus, to stay at an apartment while they figure out what to do next. Meanwhile, the Joker has freed the Penguin from Gotham State Prison to continue their crime wave. The Joker tricks Venus into asking Batman to take her to the Batcave. The Dynamic Duo take her to their base of operations (but only after making her fall asleep first). When they arrive, the Joker, Penguin and assorted thugs are revealed to be hiding in the Batmobile's trunk. Batman, however, anticipated this and none of the criminals know where the Batcave is. A figure erupts, with Batman and Robin finally ending the zodiac crimes.