Robin, Aqualad, and Kid Flash are invited to join the Justice League, but soon discover they are to be treated as junior members. When the League leaves to handle a major threat to the Earth, the three teenagers decide to investigate a fire at Cadmus Laboratories... and discover a conspiracy to create a clone of Superman.
After their capture by Cadmus security forces, Robin, Aqualad, and Kid Flash have only one hope of escape: the mysterious Superman clone, which must choose his loyalties.
Speedy refuses to join the team, causing the others to question whether the League takes them seriously. The emergence of a new villain, Mr. Twister, forces them to band together and determine if they can work together... while trying to survive.
Batman sends the Young Justice team to a Caribbean island to discover why shipments of an illegal drug, Venom, have halted. The team discovers that the drug\'s creator, Bane, has been defeated by Kobra and his cult of followers.
Angry over Superman\'s continuing rejection of him, Superboy refuses to train with the team. When Young Justice accompany android parts across the country, the parts are stolen and Superboy goes off on his own to recover them... and faces the Justice League\'s most powerful opponent.
Green Arrow has his niece, Artemis, join Young Justice. The team has to learn to accept their new teammate in short order, as the League of Shadows launch an assault with a nanotech Fog capable of stealing high-tech data files.
The team volunteers to help track down Kent Nelson, the guardian of the Helm of Fate. They discover that two villainous sorcerers have abducted Nelson and plan to use him to enter the Tower of Fate and steal the Helm. The ultimate struggle comes down to Kid Flash... who doesn\'t believe in magic.
While the rest of Young Justice enjoys some well-deserved downtime, Aqualad returns to Atlantis to consider whether to continue as team leader or pursue his personal affairs... while a supervillain launches an attack on the underwater city.
Young Justice finds themselves stranded in the Bialyan desert with no memory of the last six months of their lives, or of each other. Miss Martian is the only one who can telepathically locate her teammates and restore their memories, and discover what their mission really was.
In Taipei, Red Arrow attempts to prevent the League of Shadows from disrupting a peace conference. When he gets in over his head, he calls in Aqualad for assistance. Meanwhile, Superboy and Miss Martian have their first day of high school.
To determine who is bringing a group of ice-based villains together in one place, Batman has Miss Martian and Superboy go undercover at Belle Reve Penitentiary, posing as twin teen villains, to find out what's going on.
Robin and Artemis are forced to save their super-powered teammates when two attackers launch an assault on Mount Justice.
Young Justice fractures from within when they learn that Aqualad held back the knowledge that someone on the team was a mole. While they deal with their internal issues, the teen heroes are put under the supervision of Captain Marvel and sent to India to deal with an outbreak of animal attacks.
The Injustice League attacks cities across the world with giant plants and demands billion to stop. While the Justice League attacks the plants and distracts the villains, Batman sends Young Justice in to stop the command signal being sent from the villains\' headquarters.
Young Justice finally decides to ignore the League's orders and track down their mentor, Red Tornado, to determine whether he is truly a traitor or not. They get an assist from Zatanna, a teenage sorceress and daughter of a League member.
When an alien armada attacks Earth and wipes out the Justice League, only Young Justice stands between the planet and annihilation.
Conner Kent's pet Sphere has undergone a startling transformation, bringing it to the attention of the Forever People of New Genesis. Turns out Sphere originally belonged to them… and they want it back!
On Halloween, Artemis and Zatanna go to Manhattan for a night on the town, only to be hunted by Harm, a psycho-in-training, hiding a deadly secret...
When every adult on the planet disappears, only the team, Zatanna, and Billy Batson are left to defeat the five most powerful sorcerers on Earth.
Wally West comes oh-so-close to fulfilling his birthday wish to finally fight alongside the Justice League. Instead, a massively disappointed Kid Flash is taken off the mission and tasked with a simple delivery job. But a few deadly surprises await the birthday boy along the way…
A covert operation against Queen Bee in Qurac forces Miss Martian to finally face her greatest fears and her biggest secrets. But will she reveal those secrets to her friends - or allow what she's hiding to take down the entire team?
Superboy returns to Project Cadmus, where he learns the top-secret genetics lab may have created another Super-clone…
Red Arrow's return undercuts Artemis' confidence, while the team's mission to track down Sportsmaster threatens to expose her darkest secrets.
The Team goes undercover at the Haly International Traveling Circus to locate a thief stealing weapons technology across Europe. But a thief isn't all they find…
The Team gets a new member and a new mission - a mission that may finally expose all the Team's secrets... and all their lies!
The team finally learns the identity of the traitor in their midst, forcing a battle against an enemy more dangerous than any they've ever faced before!