After Superman is killed by The Legion of Doom so they can use his blood to summon Darkseid the League teams up to stop them but are sent back in time by Reverse Flash. While in the past the League teams up with past Superman. Once they get back to the present, they try to stop Ultraman aka the leader of the Legion of Doom but it's too late and Darkseid is summoned ending the movie in a cliffhanger.
