When an entire family is murdered with the Joker's modus operandi, Batman vows that his old foe has gone to far and that he'll make him pay for the crime that he's committed. However, upon his search for the Joker, Batman realizes that something was off about the dead bodies -- none of them had the signature Joker-grin of his usual murder victims. Batman runs back to the morgue where the bodies were taken and finds that they suddenly do have grins. Going after the only person left alone with them, Batman is knocked out from behind as they make their getaway.

Batman continues to search for the Joker and gets a lead from an underworld crime boss that brings him to the Sultan health spa, where the Joker is trying to kill a crook named Slade. Batman's intervention shocks the Joker, allowing Slade to shoot Batman and escape. While in the hospital for his wounds, Batman realizes that Slade must be trying to frame the Joker, and decides to ask the Joker for help.

However, in return for his aid in trying to track down Slade, the Joker demands no police involvement; this proves to be a difficult promise to keep, as Commissioner Gordon sends out police anyway because he cannot fully trust the Joker. After a few failed attempts, the Joker's clues lead Batman to Lock 39, an abandoned river lock system. Batman arrives, only to learn that he's been duped: Slade and the Joker have been working together in a complicated plot to try and kill Batman.

With their plot explained, the Joker opens the locks in the hope of drowning Batman. However, the Caped Crusader manages to get free, and easily knocks out Slade. The Joker, realizing that his plan is foiled, tries to escape by stealing the Batmobile, but he is thwarted by its security measures and is easily captured by Batman.

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