I shall not spoil the movie, but it is based off of FlashPoint, in which the Flash changes history for saving his mother, discovers that altering the the timeline causes changes which destroy the Earth, tries to modify the timeline so that both his mother lives and the worlds saved, but discovers that this causes so much damage to reality that it endangers his and other universes, and finally acknowledges that he must let his mother go to save reality. All of the details change in the movie for making it worth watching for those who already read the comic.

As reality starts to breakdown, we see into other universes where we see other Live-Action DC from both the big and small screen, including some projects which never made it to production. I shall stop here but recommend that you all see it. I must give a warning though:

¡This movie, just like the original comic book will hit you hard in the feels!:

When Barry accepts that he must let his mother die, he visits her 1 last time a few hour before her death. She sees a stranger openly crying and asks what his wrong. He responds that he is here to visit his terminally ill mother and will his her when she is gone. She hugs him and lets him cry on her shoulder. As someone whose mother has passed away, I am not ashamed to admit that i cried during that scene and cry now writing these words.

If you want to revisit the TimBurtonBatManVerse, I recommend this movie, but it will hit you in the feels.