The Justice League are convicted on Rimbor; Megan and Connor arrive just too late with the confession from the Light and the Reach. On earth Blue Beetle, Green Beetle, and Aqualad attack the Reach ship. Green Beetle's scarab is destroyed by Black Beetle. When Black Beetle tries to do the same to Jaime, the latter and his own scarab turn the tables on Black and destroy his scarab. During the short connection Jaime reads Black Beetle's plans to destroy the world.
Jaime explains to the rest of the Justice League about the MFDs—weapons designed to disrupt the magnetic field of the earth and disrupt weather patterns. Luthor contacts the League and tells them about software he developed to destroy the MFDs.
Back on Rimbor, the judges deliberate on the new evidence. They try to not so subtly hint at requiring a bribe, and Miss Martian and Connor convince them that showing justice would convince more to come to Rimbor with cases and bribes. While the judges debate the suggestion, Megan apologizes to Connor and discovers that he is not dating Wendy Harris like she thought. The judges release the Justice League, and as they are leaving Rimbor Vandal Savage arrives with the War World and threatens the aliens of Rimbor against interfering with earth.
The team, and what is left of the Justice League on earth, assemble to take out the MFDs, before they can go chrysalis, with Luthor's software. They manage to take all of them out, but discover that there is one more left, on the north pole. Flash and Impulse go after the MFD, but discover it has already gone chrysalis and cannot be stopped with the software. Luthor tells Flash and Impulse to run counter to the energy rotation to cancel it out.
Even their combined speed isn't enough, however with Kid Flash's help they are able to disperse the energy. But because of Wally's slower speed the energy is being diverted into him and he is disintegrated.
In the aftermath of the calamity Dick steps down as leader of the team, opting to take a leave of absence to come to terms with everything that's happened. Several loose plot threads are tied up, such as Connor and Megan getting closer to a reconciliation; and some other threads are introduced and resolved immediately, such as Cassie and Tim becoming a couple.
On Apokolips, Vandal Savage meets with Darkseid, and declares that it was business as usual. As an important note, G. Gordon—who has gone back to being a jerk—is on Apokolips.
Greg Weisman seems incapable of ending any of his series without a cliffhanger. It's the most passive aggressive thing ever, "Well, we're done now but there could be more." I love his series, but I hate how they end without fully concluding everything. I know it keeps things open for sequels, but his series never get sequels. And of course we can't blame him for Young Justice being cancelled, but I can still be frustrated when he decides to end with the promise of more, when we all know it will never happen.
But, ignoring that last scene, there's a lot to like about this finale. While the Reach were pretty much defeated last episode, and the battle against them feels more like a formality, the final conflict is sufficiently connected to the overall conflict, while at the same time being self contained enough for an episodic series.
Where I'm a little iffy is Wally's death. While his slower speed was brought up earlier, so the way he dies makes sense, it didn't fit well in the finale because Wally has not had a major role in this season. Had he been more prominent in Invasion his death could have worked in a much more thematic sense. As it is the death comes across as more of a shock event, there to make us sad. Though, the question begs to be asked, "Where was Jay Garrick in all this? I saw him at the beginning, pretty sure he could have gotten to the north pole too." Pretty sure he's faster than Kid Flash, so he could have helped and Wally wouldn't have had to die.
While Connor and Megan's relationship troubles have been front and center this season and it makes sense to have them resolve that plotline this episode, Robin and Wonder Girl's sudden relationship amuses me. We didn't get to know either character well enough to really care, so I can't say I really care. Though, I do like Tim—based on what I know of him from other sources—so I'm not adverse to him randomly having a girlfriend. Would have been nice to get more of those two though, so I could actually care about this development.
Having read the comics set between season one and two, I have to say I've had fun re-watching this season looking for clues aimed at certain developments at the end of that comic. I recommend tracking the book down and re-watching Invasion to see if you can find what I'm talking about.
And, again, that cliffhanger. I really, really hope that against all hope that we somehow get a third season down the road. Or maybe direct to DVD animated movies. I'm not going to hold out for it though. Time to see if Beware the Batman is any good.