An adaptation of "Crisis on Infinite Earths" and the final installment of the "Alternate Events" series. As a huge wave of anti-matter sweeps across the Multiverse destroying countless worlds, it is up to the heroes of the various universes to save what is left of existence. Will they succeed or will all be lost forever?

A summary of key events that occur after "Alternate Events 4: Multiversal Clashes" leading into the Crisis.

Alternate Events tie-in. What happens when the Oliver Queens of Earth-1 (Arrowverse) and Earth-21 (Smallville) wake up one morning to find that they've swapped bodies? Read and find out! Takes place six months after "Alternate Events 4: Multiversal Clashes".

Clark Kent and several other heroes from Earth-21 get involved in the final battles against Earth-1's deranged big bads: the villainous speedster known as Savitar and the star-throwing madman known as Adrian Chase. Takes place six years after the Smallville series finale, minus the flashforward, and during Arrow episodes 5x22 and 5x23.

The fourth installment of the "Alternate Events" series that begins one month after the heroes of the various universes defeated the enemy forces from Earth-X and Earth-64. It's only a matter of time before a new threat arises and not only brings everyone together once again, but leads to chaotic clashes across the Multiverse.

Marty, Doc, and their loved ones are transported to a mysterious room resembling a movie theater, where they watch the events of all three Back to the Future films, as George and Lorraine make a shocking discovery regarding a certain teenager they knew back in high school. Takes place one year after the events of Back to the Future III.