Barry Allen wakes in his office in Central City only to realize it isn’t his Central City. He’s not the Flash, and the world around him isn’t his own.
Alternate reality comics are a staple of the business (just ask the X-Men who have been doing this on a regular basis for decades now). They’re also severally limited. Nothing that happens in this reality matters outside of it. And usually few, if any, characters remember the events which took place in the other reality.
As alternate stories go Flashpoint isn’t awful. The first issue does a good job setting up the differences in the world. There is no Superman, no Justice League, Abin Sur never died bequething his ring to Hal Jordan, and Batman isn’t the Wayne we know.
I think there’s going to be plenty of bad stories in this crossover as both the Atlantis and Amazon series gear up over the weeks and months to come, but as setups go this first issue is actually better than I expected. It doesn’t hurt that this one also has an interesting version of Captain Marvel who I hope to see more of (since I don’t get any of him in the current DCU). Worth a look.