Justice League: Crisis on Two Earths (2010)
Dirs. Sam Liu + Lauren Montgomery
After an intriguing introduction we join the primary Justice League members as they build a new HQ in space; regular fans will know it as the Watchtower.
Construction is halted, however, when an intruder alarm is triggered, which is the precursor to a situation that requires their special talents; namely, a collective of evildoers who threaten to destroy everything that the League hold dear, and more.
The DC Multiverse has been used more in the comic book medium than in the animation one, but you won't need any special knowledge of the 'cosmic construct' concept to enjoy CoTE, and nor does it get too heavily into the science behind the phenomenon.
It focusses on action and adventure, mixing up expectations just enough to keep things feeling fresh.
