In one of the relatively recent Superman comics, Lightning Lad wondered what Batman would be like if both Clark Kent and Bruce Wayne were taken to the future to join the Legion. I thought it would make a good story. So here goes, from the beginning. Superman and Batman, World's Finest Legionnaires. I own nothing, nor do I seek a profit, and everything is owned by DC.

"Haven't you ever wondered what the future holds for you," Saturn Girl asked the young Kryptonian. "Now is your chance to find out."

Clark pondered the question. For too long he lived in hiding because of his powers, and he had so many questions. Saturn Girl was right. He needed to know what he was meant to do with these gifts.

"I'm going to the future Ma," Kent exclaimed, moving towards his new friends. "I'll be back in a few minutes."

"Take a sweater," Ma Kent replied, as the time bubble sprang into being.

"Actually," Brainiac replied, "We have one more stop before we return to the future. We need to pick up the other half of your team."

"I have a team," Clark asked as the bubble began to shimmer, moving through time and space. "Who is it?"

"Well, to be honest, we don't know a lot about him," replied Brainiac. "The historical files are woefully incomplete due to his own attempts to remain anonymous. Most sources provide only conjecture and legend. What we do know is that he was one of two people from your era that shaped the world, and ultimately, the universe. He was known as the most dangerous man on Earth, and was incredibly brilliant."

"I don't think this is a good idea Brainy," said Saturn Girl.

"Why not," asked Clark. "If you need help, this guy sounds perfect."

"Well," replied Saturn Girl, "what Brainiac isn't telling is that this person is horrifying. He didn't just terrorize criminals, but he generally frightened his allies too. It was said that not only could he beat his enemies, he also came up with ways of beating his friends, 'just in case.' He trusted no one and was not a team player."

"I have run the calculations Saturn Girl," replied Brainiac. "If we are going to win, we need both of them. You know what the records say."

As the bubble shimmered back into the time stream, the world around them looked very different than Smallville. It was dark and dank…they were in a cave. The sound of water trickling echoed through the chambers and only a few lights provided illumination. Shadows seemed to leap out and attack the Legion.

"Where are we," asked Clark, looking around dazedly.

"We are under Gotham City," replied Brainiac. "The man we seek is here, resting between training trips. During the period leading to his first recorded appearance, it is suggested that he traveled the world learning a variety of different tactics and fighting styles. He would return periodically to his home to prepare and…for other reasons."

"Like what," asked Clark.

"You wouldn't understand," responded Saturn Girl. "And if the records are true, you never will, fully."

"Saturn Girl, be quiet," Brainiac 5 muttered. "He's here."

The screech of bats filled the cave as a voice, echoing from everywhere graveled, "why are you here?"

Despite their years of Legion experience, Brainiac, Saturn Girl and Bouncing Boy stepped back. Clark's eyes widened, and his palms started to sweat. Then he shook his head and stepped forward. "Uh…we're here looking for your help?"

A pause. "Not interested. Leave."

"No…no you are interested," Saturn Girl replied. "You want to know how we got in here, who we are, and what we know, don't you Bruce?"

The shadows seemed to vibrate momentarily, then stilled. Finally, a ground out reply emanated from the darkness. "I don't like intruders…in every sense of the word."

Saturn Girl gasped and bolted upright, head thrown back and she started to scream and shake, then collapsed to the ground trembling, nose bleeding.

"But how," she asked.

"Don't you know," the shadows responded.

"That's it, we need to leave," Clark responded as he hurried to Saturn Girl to pick her up.

"Wait," Saturn Girl threw up her hand. Out from the darkness strode a young man, casually clothed in jeans, leather jacket, and a loose fitting t-shirt. Despite the fact that he walked into the light, the shadows clung to his eyes.

"You don't belong with this group, do you boy," asked Bruce staring intently at Clark. "Your accent says middle America, probably Kansas. Their accent is totally alien, and I have been everywhere. There clothes and machine confirm it, since I know pretty much every bit of Earth technology and cloth out there and theirs is nothing like I have ever seen. Interesting thing is that I can see Earth elements in their tech and clothes, and they use contractions, suggesting English is their native tongue, which suggests intriguing possibilities."

Bruce slowly moved towards Clark, predatorily, aware of surroundings. "But you, there is more to you than meets the eye. You are playing the geek. You may slump your shoulders, and keep your eyes downcast, but you move too carefully, as if the world will fall apart if you don't. Even when alarmed, you were careful to not move too quick, or work too hard."

Bruce's eyes shifted to Saturn Girl, who was still on the floor. "If you ever invade my mind again, I'll give you more than nightmares. Do we understand each other?" Saturn Girl nodded mutely, as Bouncing Boy moved to pick her up. Clark was still staring at Bruce in wide eyed concern, given how the man had figured out Clark's secret.

Bruce moved towards Brainiac. "Talk. Then get out."

Brainiac began, "we are representatives from a group that fights against threats of all kinds. We are from the future, which would explain all of the anomalies that you found in our behavior. We have traveled back in time to obtain two individuals, you and Clark, who can help us against an especially pressing threat which we cannot address by ourselves."

Bruce nodded and said, "so by choosing us, and what would have to be well our documented skills in your time, you are attempting to gain advantage. But why now, as opposed to later when we have both developed our skills more? Given the girl's abilities, the boy's apparent physical skills, and your…nature, why obtain a 20th Century human with no such gifts? And while I am no expert in physics, aren't paradox concerns?"

Brainiac shook his head, "you will not get me to underestimate you Mr. Wayne, I know your strategies. You are an expert in physics, at least by the 20th Century definition, and in chemistry, biology, engineering and genetics, with functional PhDs in each." Clark's eyes widened at this revelation as he began to think that maybe his secret wasn't quite so self-evident after all. "I can tell you that in 1000 years many of the paradox concerns you have can be mitigated given sufficient calculation and safeguards, part of which is the reason why we are getting you before your talents are fully developed. As for why you, all I can say is that while history may tell us you are not the easiest person to work with and that you lack any meta human ability, your human talents more than make up for any deficiencies."

Bruce tilted his chin up for a moment, and then nodded. "I presume your device can bring me back to this exact place and time upon completion of our task."

"Within a few minutes," Brainiac confirmed.

Bruce strode to the time bubble and responded, "let's go."

Brainiac followed without evident hesitation or surprise, while Clark and the rest of the Legion wer slightly more surprised. As Clark helped Bouncing Boy and murmured, "man I don't like that guy."

Saturn Girl looked over, and lightly smiled. "Well…that will change."