Are superhero comic books science fiction? I'm not enough of sci-fi aficionado to jump into this debate, but I can see how arguments could be made on both sides. For starters, these comics feature humans who have powers beyond those of a normal person, enabling them to fly, shoot lasers from their bodies, etc. That sounds pretty science fiction to me. On the other hand, most are set in the present, and focus more on crime-fighting than on technology. This isn’t to say that superhero stories can’t branch out into sci-fi. For decades, stories in DC Comics have focused on the existence of parallel worlds which contain characters similar too, but often quite different from, those found in the company’s biggest titles. This type of tale has been brought to an animated movie with Justice League: Crisis on Two Earths.

As Justice League: Crisis on Two Earths opens, we witness Lex Luthor (Chris Noth) and someone who looks like The Joker breaking into a high-security building to steal a small device. When they are pursued by super-beings, Luthor escapes and, using a machine, disappears. When then shift to a satellite above Earth, where the Justice League -- Superman (voiced by Mark Harmon), Batman (voiced by William Baldwin), Wonder Woman (voiced by Vanessa Marshall), J’onn J’onz (voiced by Jonathan Adams), Green Lantern (voiced by Nolan North) and The Flash (voiced by Josh Keaton) -- are hard at work, when Superman receives a call that Lex Luthor has been captured. Superman interrogates Luthor and realizes that he’s from an alternate world. Luthor explains that in his world, he is the leader of the Justice League, and a group of super-villains, called The Syndicate, have taken over. He implores the Justice League to help him. All but Batman go with Luthor, and soon find themselves fighting their evil mirror images in order to save his world.

The appeal of parallel worlds stories is a simple one -- we want to see a place which is similar to our world, but has just enough differences to be similar or creepy. Justice League: Crisis on Two Earths certainly delivers on this front. The Syndicate is comprised of super-powered beings whose abilities directly mirror those of the Justice League -- there’s Owlman, Super Woman, Ultraman, Johnny Quick, and Power Ring just to name a few. We also get to see Lex Luthor cast in the role of not only hero, but sensitive and light-hearted hero at that. The story does a good job of brining in politics and crime to flesh out the story somewhat.

Justice League: Crisis on Two Earths beams us The Flash on Blu-ray Disc courtesy of Warner Home Video. The movie has been letterboxed at 1.78:1 and the Disc contains a VC-1 1080p HD transfer which runs at an average of 18 Mbps. The image is very sharp and clear, showing no grain and no defects from the source material. I would assume that this is a digital-to-digital transfer, as the image is razor sharp and displays an impressive crispness. The colors look fantastic, from dark hues to pastels. The image is never too dark or bright. The HD transfer doesn’t reveal any jagged lines or problems with the animation. The Disc carries a Dolby Digital 5.1 audio track which runs at 48 kHz and a constant 640 kbps. The track delivers clear dialogue and sound effects. While I would have preferred a lossless track, the sound here is still pretty good. The action sequences provide notable stereo and surround effects. These effects are nicely detailed and show good separation. The fight scenes also throw in some mild, but effective subwoofer effects.