Each company has mini series set in their own individual multiverses.
DC:
The Book of Revelation. This stars characters associated with the Supernatural and Paranormal as the JLDark are investigating the God sphere and how the different pantheons are falling apart as fallen warrior angels are killing off mythological gods.
The Fall of Oa. The different emotion corps are losing their powers as each of their batteries are being snuffed out by a strange cosmic force that they have never dealt with before.
The Time Trap. Superman returns from Warworld to discover HIS Legion has came from the future to warn him of the false Legion that has helped establish the new United Planets of the 21st century that has been orchestrated to destroy the time stream by the Time Trapper and his colleague, Hank Henshaw in the form of the aged up Jon Kent.
MARVEL:
The Ragnorok of Souls. Dr Strange and Thor must stop Hela and Loki from unleashing the true Ragnorok as Asgard is in flames and the Norse Gods fall into Hel.
Empyre’s End. The Skrulls and the Kree must join together with the help of The Marvels and Hulkling to defeat an unknown threat from destroying their galaxy
The Deal of Destruction. Mephisto’s deal with Peter Parker back during OMD has finally set up consequences that shake the world as a May Day from a different timeline has dropped in in hopes of righting the wrong that was “The Deal” before time collapses on itself.
After these end, a one shot from each company are released. In DC’s Superman, Booster Gold, Batman, Damien and Kyle Rayner go in search for the true Jon (Kyle because he is the only ring slinger with powers and Booster, because, well, time). They find him being held by the cosmic force that destroyed the power batteries. In MARVEL’S, Captain America, Carol Danvers, Spider-girl from the alternate universe and Scarlet Witch travel to the ends of the universe to use the infinity gems to stop the destructive force from destroying the multiverse only to discover the cosmic force.
The cosmic force in both universes is a shadowed version of Access called The Joining, whose purpose is to destroy all things throughout all multiverses in order to remake reality in his image with out the pantheons of gods or space empires or cosmic police to get in his way. The Joiner has been driven mad by having to live in all realities at once and his mind has been broken. Over the years, he has SECRETLY organized this CRISIS to make things unified so he can live one life, not multiple.
This leads into DC AND MARVELS…Secret Crisis.