Justice League: The Flashpoint Paradox (2013)
Flashpoint was the mini series that transitioned DC into the new 52 continuity. I only read the Batman portions of it, so most of it was really unfamiliar to me.
The Flash (Barry Allen) is at his mother's grave, wishing he could have prevented her death when he was a child. After an encounter with Zoom, he's motivated to save her. It's unclear what exactly Flash did, but the entire world has changed because of it. Europe is destroyed by the Atlantians and the Amazons invade Great Britain. Both have declared war on the rest of the world and on each other. Barry never got his powers, Bruce's dad became Batman after watching his son die, it's a pretty awful world.
That's about as much I want to give away. A ton more happens and it's awesome. I think it's one of the best DC animated films they've made and they've made some killer home runs. This is raw and often times just so dark, but it's amazing.
Whoever writes or directs this stuff needs to give the live action people tackling Superman/Batman a crash course on how these core characters interact when meeting for the first time.