Batman wiped at his eyes, lungs still burning. The Batmobile's taillights were gone.

  He spun to the Batcomputer, fingers typing commands. No response. Wrong system. Not his cave. Not his world.

  His eyes flicked to the Batcycle.

  Batman swung into the saddle and kicked the ignition. The engine thundered alive. He tore up the tunnel after them.

  ---

  BC activated probe 12,847 as it crossed into a new universe. The sensors came online, feeding him visual and audio data. He processed the incoming stream—a high-speed chase through city streets.

  The Batmobile tore through narrow roads while a figure in a purple suit drove, ughing maniacally. A blonde woman gripped her seatbelt in the passenger seat. Behind them, someone on a Batcycle gave pursuit.

  Batman. Joker. Harley Quinn.

  BC opened a communication link to Ultimate Bruce Wayne.

  "Mr. Wayne," BC said.

  "Go ahead."

  "Do you remember the Batman you told me about? The one who ended up causing his world and his Gotham to be destroyed because he would not turn away from his no-killing rule?"

  Ultimate Bruce Wayne's thought came through the link. "Yes."

  "I think this might be him. Do I have your permission to send you the feed?"

  "For sure."

  BC transmitted the visual data stream. Through his probe's sensors, he watched the chase unfold. The Batmobile sideswiped parked cars and sent vendors scattering. Pedestrians dove out of the way as the vehicle careened through intersections. Then impact. The Batmobile smmed into a concrete wall. Joker stumbled out, blood trickling from his forehead but still grinning.

  Batman arrived moments ter. He flipped off the Batcycle, nded on his feet, and immediately engaged Joker in combat.

  BC analyzed the fight through his probe's feed. This was more brutal than standard encounters he'd observed. Batman's strikes carried serious intent. When Batman grabbed Joker's head and smmed it into the Batmobile's side, BC calcuted potential for severe injury.

  During the violence, Harley Quinn slipped away.

  Batman pinned Joker to the ground. Joker looked up at him, still ughing through split lips.

  "Do you realize you could've killed people?" Batman demanded.

  "Yeah, I know that," Joker replied. "Shame I didn't get to do it."

  "You're a monster."

  Joker's grin widened. "Why are you repeating things we already know? We're both monsters."

  "I'm nothing like you."

  "Yes, you are. You missed me, didn't you?"

  Batman raised his fist. Joker smiled up at him expectantly. "Can you finally do it, Batsy? Are you finally going to break your no-killing rule?"

  Batman's fist hesitated in the air. "No."

  He struck Joker precisely in the head. BC's sensors detected the impact was calibrated to render unconsciousness without fatality.

  "Yep, he hasn't changed at all," Ultimate Bruce Wayne's announcement came through the link. "He's going to repeat the same things he did that destroyed his Gotham. He's gonna take him to that universe's Arkham, and Joker's going to escape."

  BC immediately began running data searches through that universe's internet networks. His probe accessed public records, news archives, and facility reports. Within seconds, he had Arkham Asylum's complete escape record.

  "The data confirms it," BC transmitted back. "Arkham Asylum in this universe has an 89.7% recapture and escape failure rate. Seventeen documented Joker escapes in the past decade."

  Ultimate Bruce Wayne's voice came through quietly, tinged with sadness as he nodded his head. "He hasn't learned a thing. I wonder how long it'll take for that world to be destroyed by these two."