Ep 21. Mystery in Space

In Justice League Unlimited season 1 episode 21, "Mystery in Space," the Justice League encounters a group of alien superheroes who are in need of their assistance. The aliens, who call themselves the "Thanagarians," explain that they are on a mission to stop an enemy known as "Gordanians" from destroying the universe. However, they are unable to do it alone and require assistance from the Justice League.

The Justice League agrees to help and sets off on a space mission to stop the Gordanians. Meanwhile, Flash, who is left behind due to his inability to breathe in space, stumbles upon a mystery on Earth. He discovers that someone has broken into the Justice League headquarters and stolen a device called "Feligra," which is capable of controlling all forms of technology.

Flash alerts the other Justice League members about the theft and they quickly realize the severity of the situation. They suspect that the Gordanians may have been behind the theft and that the Feligra device could be used against them. So, the team splits up into two groups - one to continue the space mission and the other to investigate the Feligra theft.

As the space mission continues, the team faces various obstacles and challenges. They discover that the Gordanians have set up a trap for them in the form of a black hole. The team manages to escape the trap but decides to change their strategy. They realize that the Gordanians are attempting to attack the Thanagarians' home planet and decide to go there to stop them.

Once they arrive at the Thanagarian home planet, the team is greeted by a stunning revelation. They find out that the Thanagarians had been planning to invade Earth all along. The team is shocked and confused as they had believed that the Thanagarians were their allies. The team then discovers that the Feligra device was taken for the purpose of launching a sneak attack on Earth.

In the meantime, Flash and Martian Manhunter are investigating the Feligra theft on Earth. They gather evidence and piece together the identity of the thief - a member of the Justice League who has been blackmailed by the Gordanians. Flash and Martian Manhunter confront the thief and recover the Feligra device.

The episode ends with the Justice League learning of the Thanagarian invasion plan and working to stop them. The team faces a difficult decision as they must decide whether to ally themselves with the Gordanians, with whom they have always been at odds, to stop the Thanagarian invasion.

Overall, "Mystery in Space" is a thrilling and action-packed episode of Justice League Unlimited that introduces new characters and complex plot lines. The episode explores themes of trust, betrayal, and the choice between allying oneself with former enemies for the greater good. With its stunning visuals, intense action sequences, and high stakes, "Mystery in Space" is a must-watch for any fan of the series.