Batman: The Joker Is Purina Shark Chow!

A five man clown mask-wearing gang is robbing the mob-owned Gotham National Bank. They proceed to rob the bank in groups, and at each step, one of the men finds out that the other was assigned by the Joker to kill him, which continues until only two are left in the lobby with the bags of cash. A school bus suddenly bursts through the bank wall, killing one of them, and the only remaining clown pulls off his mask, revealing a face painted white with makeup, his scarred lips forming an unnaturally wide smile, which is painted blood red. This man is the Joker, who proceeds to load the bus with cash and drive out of the bank into a row of buses, making his getaway among them. That night, a meeting taking place between several mobsters and the Scarecrow is cut short by the arrival of multiple Batman impersonators—a group of vigilantes who are inspired by Batman's efforts and seeking to lend him a hand. The real Batman shows up and subdues everyone, but suffers injuries which lead him to design a more versatile suit. After the conflict, Batman meets with and Lieutenant James Gordon, and the two discuss recruiting Harvey Dent, Gotham's newly elected D.A., to take part in their plan to eradicate the mob and the Joker's involvement with the bank heist; Batman can continue his vigilante-style law enforcement, and Dent can be the face of the campaign to end criminal activity in Gotham, becoming the type of hero that Batman cannot be.

As Batman keeps to the shadows, he uses his alter-ego, Bruce Wayne, to promote Dent in the campaign. Bruce's difficulty is compounded by the fact that Dent is dating Bruce's would-be girlfriend, Rachel Dawes. This puts a strain on Bruce and Harvey's relationship, as well as on that of Bruce and Rachel. Meanwhile, the mob bosses meet to discuss how to handle Batman, Gordon, and Dent. The meeting is interrupted by some men who bring in a TV, on which Lau, a Chinese mobster accountant, appears via conference and tells the mobsters that he has moved their money to Hong Kong to prevent the police and the new D.A. from seizing it in an imminent bank raid. The Joker arrives unexpectedly, offering to kill Batman at a price of half of the accumulated money. Joker then proceeds to kill an opposing mobster, Gambol, to further his operation and hire more men. With the help of Lucius Fox, Batman follows Lau to Hong Kong and successfully and brings him back to Gotham, depositing him on the doorstep of the Gotham City police department. This turn of events motivates the mobsters to agree to the Joker's terms. The Joker uses the local news to declare his intention to kill people each day until Batman turns himself in to the police. When the Joker begins killing public officials, including Commissioner Loeb and Judge Surillo, who presided over the mob trials, Bruce decides to turn himself in. Before he can do so, however, Dent announces that he is Batman, and allows the police to take him into custody to draw the Joker out of hiding. When the Joker attempts to kill Dent in transit, Gordon and Batman intervene and arrest him.

Gordon is promoted to commissioner for his efforts, and heads to an interrogation room to confront the Joker. Gordon gives the Joker an opportunity to talk, and when the Joker refuses, Gordon turns him over to Batman for interrogation. Batman beats the Joker, who finally reveals that Rachel and Harvey have been abducted and each of them has been taken to an address on a side of the city opposite the other. He taunts Batman, telling him that he does not have time to save both of them. Batman speeds off to save Rachel, while Gordon and the police head after Dent. However, the Joker deliberately gave Batman false information, and unbeknownst to either Batman or Gordon, Batman is going after Dent and Gordon after Rachel. Harvey and Rachel each awake to find themselves tied to a chair, and while each is in a warehouse that is rigged to explode, they find that they can talk to each other via some audio equipment that has been set up near them. Harvey tries to escape his bonds by knocking over a chemical-filled oil drum nearby, but causes his chair to fall to the floor in the process. The left side of his face makes contact with the cement floor, and the chemicals from the tipped drum rush toward him, causing him pain as they start to burn through the skin. Back at the police station, the Joker, who has planted a cell-phone bomb inside one of the prisoners, detonates it as a means of escape, taking Lau with him.

A few minutes later, Batman arrives at Dent's location in time to save him, but Dent is upset that Batman isn't rescuing Rachel. The building explodes, exposing Dent's face to the ensuing flames, which ignite the chemicals on his face, severely burning him. Gordon does not arrive in time to save Rachel, and she is killed when the other warehouse explodes. Dent is taken to a hospital, where he is driven to madness over losing Rachel. The Joker frees Dent from the hospital and Dent, who blames the Joker for Rachel's death, flips a coin to decide whether to kill the Joker with a gun that the Joker provided. The coin lands on tails and Dent shoots the Joker, killing him! He then leaves the hospital and seeks out Batman! Meanwhile, Harley Quinn goes to Gotham General Hospital and finds the dead body of the Joker! Harley Quinn is very upset! Harley Quinn takes the body of her beloved Mr. J and leaves Gotham General Hospital! Harley Quinn then takes the Joker's body to the Gotham River and gives the Joker a burial at sea! The Joker's body lands in the water! The Joker's body is now Purina shark chow for the shark babies! When Dent meets up with Batman, Batman confirms that the Joker was responsible for Rachel's death! Batman and Dent then reconcile and the two continue to fight crime in Gotham City together!