Young Justice, Cartoon Network
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Caution: potential spoilers.
I should say that there's a comic book I've never read which bears the same title as this series, but I don't believe the show is directly based on that. But most of the characters are familiar to me from various alternate incarnations (though there are some differences here, because the show is set on a different Earth in the DC multiverse). There was a one-hour movie that aired in November 2010, though the series itself doesn't begin until January 2011. (I should also mention that the series is not directly related to the DCAU continuity or any other animated series based on DC comics.) Anyway, at the start of the movie, we see four separate superhero teams: Batman and Robin, Green Arrow and Speedy, Aquaman and Aqualad, Flash and Kid Flash. Each team is fighting a different cold-themed villain, but they're also all more interested in a meeting that is to take place later that day. After defeating their enemies, they head to the Justice League HQ, for a first step at initiating the sidekicks into the League. However, Speedy is seriously offended that they're all still being treated like sidekicks, and the process is too slow for him. So, he quits, and leaves. Meanwhile, there are reports of two separate problems that might require the League's attention, and the established heroes head off to take care of the one that seems more important, telling the sidekicks to stay behind.
Robin hacks into the League's computer to learn about Project Cadmus, where there was a fire (the lesser of the two reported problems). He, Aqualad and Kid Flash decide to disobey orders, and head over there to take care of the problem themselves. They soon discover that the facility is much larger than it appears, having 52 secret levels below ground. They investigate, and end up discovering tons of bioengineered mutant creatures called biomorphs, apparently being bred as weapons. They also discover a clone of Superman, which was created 16 weeks ago, but has already grown to appear to be a teenager (whose mind had been programmed with knowledge and was being controlled by his creators). The scientist in charge of all this was using biomorphs to telepathically control everyone, including the chief of security, a superhero called Guardian. The sidekicks manage to free Superboy, who eventually meets up with another biomorph named Dubbilex, who works with Cadmus but helps Superboy and the others escape. They have to battle the head scientist, who drinks a serum that turns him into a monster called Blockbuster.
In the end, Superboy, Robin, Aqualad, and Kid Flash all make it out of the facility, which they bring crashing down. Then the Justice League shows up, and the sidekicks demand to be allowed to work together as their own team... sidekicks no longer. So, a base is set up for them, and they are introduced to Martian Manhunter's niece, Miss Martian, who will be the fifth member of the team. (And when the series gets going, there should be lots more young heroes added to the group.) Meanwhile, the board of directors of Cadmus, who call themselves "the Light," place Guardian in charge of Cadmus. Freed of mind control, he intends to turn the Project around, though they still believe they can control him through subtler means. They also believe that Superboy's newfound freedom can ultimately be used to their advantage.
That's all I can say for now, but so far it seems pretty cool. I like the animation, the action is good, the story is good, the characters are good, the humor is good... the whole thing has a great deal of potential, so I look forward to seeing where it all goes from here. Unortunately, I lost access to Cartoon Network in June 2011, so I didn't get to see very much of the series.