Hey guys too excited to answer questions so here you go.
Warning: i am not affiliated with dc comics or Cartoon Network
"And stay down Animo!" yelled Four-arms as he pointed victoriously at his defeated enemy on the ground. "Ugghhh Ben! Quit gloating! Plumber HQ sent us here to meet the representative from the Young Justice League." Gwen stopped talking when an arrow flew past here and Artemis zip lined down on it. And KF zoomed in saying "Don't you mean representatives?" Ben chuckled at the childish thought of his cousin being corrected for the first time ever Gwen smacked his head. "Ooh I like her already." said Artemis. "Anyway's the names Flash." Wally said as he zoomed behind Ben who had transformed back to his 18 year old self. "Kid Flash." Ben jumped as Wally surprised him and said back "Tennyson, Ben Tennyson. And this is my cousin Gwen and her boyfriend Kevin Levin." After all the pleasantries were over Artemis got down to business. "Ben, Gwen, Kevin. You have all heard how the Justice League has been committing crimes over the past couple month's?" Ben replied with his 10 year old attitude "Uhhh Yeah." which was met with another smack to the head by Gwen who replied more nicely. "Yeah when the Man of Steel goes bad the Plumbers usually picks that up." Artemis got back on task. "Well that's actually what we wanted to talk to you about." she handed them all League memberships. "We need you three to come with us to the Zeta tube here in Bellwood." they followed the two hero's to a abandoned tool shed near Grandpa Max's old garage where he would fix up the Rustbucket "This old place? You'll never get it open tried once when I was ten not even Diamond Head's sharpest crystals could cut that lock." Ben was cut off when the familiar computer voice of the Zeta tubes came on. "Artemis Y-J-5, Kid Flash Y-J-3, newly recognized League membership cards authorized, Benjamin Tennyson A.K.A. Ben 10 Y-J-10, Kevin Levin A.K.A. Kevin 11 Y-J-11, Gwendolyn Tennyson Y-J-13 New members accounted for please enter Zeta tube one at a time welcome to The Justice League." all three of the legendary hero's looked down at their cards and Ben and Kevin said in unison "Cool..." when they looked up KF was gone and Artemis stood there in front of the tube and said "Just walk through naturally don't stop walking no matter what." they did as they were told and were greeted with darkness and coldness as they stepped into the original Bat-cave. Gwen spoke with a crack in her voice at the sight of the legendary location "cool..." they walked onto the platform and was greeted by two of the newest members. "Greetings Earth friends!" the Tameranian hugged all three with immense strength but put them down a second later and was then greeted by Nightwing. "Hey there, welcome to the Bat-cave I see you have already met Star-fire and this is cyborg." the metal man outstretched his hand to Ben and he shrieked when Cyborg almost crushed his hand. "oops sorry hehe new arm still adjusting the strength setting." Nightwing got a call on his earpiece and a wall in the Bat-cave opened at his command which revealed nearly 100 hero's all mingling or working out or both. All three of them said in unison "Cool..."
I know you guys not that detailed but im tired and I felt like writing so I comprimised.