Hi! This was bouncing around in my head for a while and I figured I might as well write it :) The timelines might be a little off but I hope you enjoy!
Disclaimer: I don't own anything in this story.
It was an almost-average mission debrief. Lex Luthor invented a new plot to get rid of Superman. To make a long story short, it involved a sonic death ray with kryptonite, quickly made plans, danger and reckless bravado. The last item that occurred, however, bothered Batman. Very much. From his chair, he growled about the lack of following orders - only Green Lantern had listened to his plans (must be the soldier instinct). He was also the only one who was safe and unscathed.
"Aw, come on, Bats! We know we should've listened to your plan but, hey, we're alright and we won!" Flash attempted to stop the tension in the room, failing.
"You won? Is that what's important to you - winning? You may have lived this time but, believe me, there is no guarantee that you won't die next time!" Batman snarled, fixing the Flash with a terrifying glare that made him and all of the other inhabitants of the room shudder. You couldn't get used to that look.
"You know, I agree with Batman. We're getting reckless out there and not following orders." Green Lantern told them.
"I, too, agree with Batman - you don't know how dangerous these situations are!" J'onn inputted.
"Well, we went in there basically blind. How were we to know that Batman wasn't impaired, too!" Wonder Woman protested. About five minutes of arguing later, Batman stood up.
"Where are you going?" Superman called, instantly stopping he arguments.
"I'm done," Batman explained viciously, "I'm done with caring or worrying about people who don't care about their lives. Enough bad things have happened to me to know that liabilities cause unnecessary grief and almost all of you are liabilities so I'm done. I'm out of the Justice League." He left to stunned silence. Quickly, the superheroes' minds caught up to the situation and they were calling for the genius who didn't reply.
Batman was beyond angry. He was beyond disappointed. He told them from the beginning, he wasn't a team player. He knew that they'd come after him. He'd have to leave Nightwing in charge of Gotham while he was gone - a year tops. He arranged to meet him and told him everything, including that he had to call if there was even a whisper of trouble in Gotham that he might struggle with, like deranged serial killers. Nightwing seemed excited at the trust level he was at. Batman packed a bag and quickly wondered where he could go. They didn't know about Bruce Wayne but he still intended on fighting crime. Where to go . . .
The realization hit him like a ton of bricks. So simple, he wondered why he hadn't thought of it yet. Tony Stark, Iron Man, his best friend. Bruce Wayne boarded his private jet and told the pilot to go to New York City. On the plane ride, he called Tony, who seemed delighted. He'd have an entire floor to himself within 30 minutes. Since both of them had parents with their own companies, they were often dragged around for parties. The two children became friends quickly and became inseparable. They still told each other everything - Tony was one of the few people who knew everything and understood some of it. Finally, the jet touchEd down in La Guardia. Bruce looked out the window, his handsome face a mask of indifference, until he saw the car with "STARK INDUSTRIES" emblazoned on it. A beautiful smile flew across his face as he handed the pilot his generous tip and left the jet, heading for Tony Stark's car.