I decided to make my take on HP and YJ crossover. Pairings still to be determined. Enjoy and review.

Independence Day

Hall of Justice Washington DC 14:00

A group consisting of eight people was approaching the famous HQ of a Justice League. The group consisted of four heroes: Batman, Aquaman, Flash, Green Arrow and their partners or how people tend to call them "sidekicks" Robin, Aqualad, Kid Flash and Speedy. Upon entry Martian Manhunter and Red Tornado greeted the group. Once heroes and partners entered they saw another person sitting in one of the chairs. The figure was in a dark green costume with a hood that was currently down next to the chair there was a pitch black cane with silver raven on top. The guy himself was a bit taller than Robin with unruly black hair and emerald green eyes.

"Robin, I'm glad to see you again." New guy said.

"It's been a while Arcane. How is it going?" Robin greeted his friend.

"Nothing new in my life other than training, researching and catching criminals and that is more than enough of excitement." Arcane answered.

As they were about to continue this conversation Manhunter decided to attract their attention:

"Robin, Aqualad, Speedy, Arcane and Kid Flash welcome. You now have access to our kitchen, gym, and the library." The green-skinned man greeted the teens with a smile before taking them in to another room. "Please make yourselves at home." He then together with other adults went to a door 'Members only'.

"A quick debrief to discuss why four Ice villains attacked on the same day.. We shouldn't be long." Walking to a door that red 'Members Only' a small camera came out of the ceiling, and scanned each man.

"Recognized Batman 02, Aquaman 06, Flash 04, Green Arrow 08, Martian Manhunter 07, Red Tornado 16." The computer spoke as the heroes took a step to the door.

"That's it?!" They turned to Speedy who stared at them with a hard stare before continuing. "You promised us a real look inside, not a glorified backstage pass."

Aquaman looked at him before speaking up. "It's the first step. You've been granted access few others have had."

Speedy gestured to the tourist at the window on the ceiling."Who cares what side of the glass we're on?"

Green Arrow walked over to him, and spoke up. "Calm down Roy. You just need to be patient."

Speedy just angrily glared at him. "What I need is respect."

Then Arcane spoke up "Are you sure you want respect? Or do you want fame, attention of ladies and other stuff down the list? Maybe you forgotten that respect is earned not given."

"I earned my respect…" Speedy started.

"And yet you are throwing a temper tantrum as soon something goes wrong." Raven haired boy said matter-of-factly.

"Oh yeah, they treat us like kids, worse like sidekicks. We deserve better than this." Speedy looked at the other three as they looked at each other and simply shrugged. "You are playing their game? Today was supposed to be THE day, a step one on the road to full membership."

Kid Flash answered "Yeah sure, but I thought step one is a tour of HQ."

"Except for the fact that hall isn't real HQ. They have a secret H.Q. A giant satellite that orbits around Earth, I thought they told you that it is a front for tourist and a pit stop to get to Watchtower." Batman directed his glare to Green Arrow as eyes of other sidekicks went wide.

"I know I know but I thought we could make an exception." Green Arrow said with hope but narrowed eyes of Batman answered the question. "Or probably not."

"Stand down son you are not helping your cause." Aquaman tried to defuse situation.

"Or what, are you going to send me to my room? I'm not your son. I'm not even his." He pointed to Green Arrow before grabbing his."I thought I was his partner. Not anymore." Throwing the hat down and Speedy turned and walked past the other teens. "They were right about you. You're not ready." And he exited through the door.

Arcane turned to the Green Arrow "Did he always had such a big stick up in his arse?"

As Arrow was about to defend his protégé an alarm on the computer went off and everybody saw Superman on the screen. "Superman to the League, a fire broke out on the Project Cadmus."

Batman entered some data in computer "I've had my suspicions about project Cadmus for some time now. This will present a perfect opportunity to investigate it. "

But he was disturbed by another emergency. "Zatara to the League Wotan is planning to use Amulet of Aton to blot out the sun. I request a full League response."

"Superman?" Batman looked at the Man of Steel questioningly.

"It's a small fire local firefighters can deal with it."

"Alright, we will handle Wotan. Batman out" He turned to the teens "Stay here."

"What? Why?" Robin asked

"You are not trained." Flash said

"Since when we are not properly trained what we have been doing up until now?" Kid Flash asked.

"What I mean you are not trained to be part of a big team." Flash answered

"There will be missions, when you are ready." Aquaman added

"But for now stay put." Batman and turned to the door.

Green Arrow turned to Manhunter "Glad you didn't bring You-Know-Who?"

"Indeed." Martian said as he went to follow Batman and the rest of the team.

"I thought they trusted us." Aqualad said

"Trust? They don't trust us with the basics. They have a secret HQ in space." Kid Aqualad looked down for a second. "What else aren't they telling us?" Robin snorted before speaking up. "I've got a better question. Why didn't we leave with Speedy?" Both KF and Aqualad looked down.

"What is 'Project Cadmus'?" Aqualad asked.

"Now this sounds like a productive question." Arcane spoke as three heroes have forgotten about his presence in the room.

"What do you mean?" Robin asked.

"Temper tantrums are not the best way to prove that you are worthy of respect but solving their case before them…" Arcane started

"Can actually be a poetic justice." Aqualad finished the thought.

"And we all know they are all about justice." Kid Flash quipped.

Arcane gestured to computer "Rob, do your magic."

Robins hands started to fly over keyboard "Access denied" was a response from computer.

"Huh, wanna bet?" Robin smirked before typing again having several screens pop up. "Dude, how are you doing this?" Robin continued to type before answering.

"Same system as in the batcave and..." Hitting enter, the computer spoke up. "Access Granted." A picture of a building came up. "Project Cadmus, a genetics Lab, here in D.C. if Batman's suspicious that's more than enough to check it out."

Aqualad sighed before speaking up. "But they did tell us to stay put." Robin just looked at him with a smirk. "From the sun mission, not this one."

Kid Flash quickly grabbed Robin's shoulder. "You're serious? If you're going, I'm going."

"What about you?" Robin turned to the Arcane.

"Gentleman I think it is a great time for our first team mission. Though we must be careful and pull this off before adults will try and bail us out." Arcane answered smirking.

"You right otherwise we will just prove them that we are not ready." Aqualad said.

AN: I will make back story of Harry in this AU during later chapters.