A/N: For the sake of this story, the League all knows each other's secret identities, but not the details surrounding them.
"Where are we?" Superman questioned as they gazed around the black landscape that had surrounded them since they awoke a few minutes ago. The rest of the founders also gazed around, examining everything around them to find some clue as to where they were.
For as far as they could see there was infinite darkness. Not just darkness, like a shadow, but a complete absence of light except for the area lit by Green Lantern's ring, which cast an eerie green glow onto the surrounding blackness.
A voice suddenly boomed out all around them, "Welcome, Justice League. It is long overdue that I exact my revenge upon you for derailing my plans." Unfortunately it was a voice that they all recognized. Dr. Destiny. That explained where they were; trapped in a collective dream.
The voice continued, "The first time we encountered one another I isolated you and confronted you all with your darkest fears. But that plan failed. Now, I know precisely how to defeat you all. By confronting you with memories of great pain from one who you consider your ally. The one who defeated me. The Batman. You are all currently trapped within the nexus point of Batman's memories. You will then be forced to endure the darkest points of the Batman's life, forced to feel the emotions that are attached with them and forced to forever live with the knowledge of how damaged the Dark Knight truly is." He paused before saying, "That is, if any you survive with your sanity intact." The voice faded away, chuckling as it did so.
Before the League could question Batman about his past, the darkness began to shift and stir around them, twisting into recognizable shapes. Building began forming around them, leaving them in a dark, dank alleyway that was littered with filth.
Batman breathed in sharply, already knowing where the first memory was. technically it was the first memory. The memory that birthed the Batman. The cesspool that gave rise to Gotham's Dark Defender.
No one remembers the true name of the alley, for its description long ago replaced it's name. Crime Alley. The place where it all started, with a punk with a gun.
It wasn't long before the scene had settled into the form of a dark alleyway. Soon the League could hear the sound of a happy child chattering away excitedly. A few seconds later he rounded the corner with his parents not far behind. The father and son appeared to be talking about energetically about Zorro and sword fighting, while the mother watched with a smile on her face. The League, except for Batman, could not see how this was a horrible memory. That quickly changed.
The League watched in horror as the memory unfolded. They all (except for Batman) tried to intervene and prevent the atrocity from being committed. But they couldn't interact with anything, they drifted through this world like ghosts. None of the League needed to ask whom the mother and father were, they had all recognized the resemblance between the boy and the Batman. They just looked at him with sadness and sorrow clear on their faces. Batman simply ignored them and maintained a stoic expression on his face.
The scene around them began to dissipate, leaving them with the mental image of an eight-year old Bruce knelt between the murdered bodies of his parents. They had all heard the promise made on the blood of his parents. The vow that sealed his fate as the Dark Knight. The oath that he had maintained to this day and would continue to do so for as long as he could.
Not long after the voice returned. "Well, that was a nice appetizer. I think it is time to move onto the main course!"