From the publisher's website:
The End of the World is just the beginning...
Dozens of supervillains dream of destroying the world, but only Omega, Lord of the Terminus, has the means to destroy all Earths, parallel dimensions without end. Only four worlds remain, the lynchpins of the omniverse, and only the heroes can save them!
In this new, updated second edition of the first published Mutants & Masterminds adventure, your heroes travel to other Earths in order to save the whole of creation, confronting evil twins, super-apes, and über-Nazis, as well as the all-powerful Omega himself, in the Time of Crisis!
Time of Crisis makes an excellent companion adventure to the Worlds of Freedom sourcebook, introducing heroes to the omniverse, the Terminus, and several of the worlds featured in that book, including Erde, Earth-Ape, and Anti-Earth.
What are you waiting for, hero? It’s time to save worlds!