The game takes place after Raiden, Earthrealm's god of thunder, and Superman, Metropolis' defender, repel invasions from both their worlds. An attack by both Raiden and Superman simultaneously in their separate universes causes the merging of the Mortal Kombat and DC villains, Shao Kahn and Darkseid, resulting in the creation of Dark Kahn, whose mere existence causes the two universes to begin merging; if allowed to continue, it would result in the destruction of both. Characters from both universes begin to fluctuate in power, becoming stronger or weaker.
The game features a story mode, playable from two different perspectives. The perspectives consist of one segment from the DC Universe side, and one from the Mortal Kombat side, each split up into various chapters. Depending on which side players choose, the characters from one universe see those from the opposite universe as the invaders of their own. The player has the ability to play as all the characters in the story mode at one point during development, but the story mode ultimately lacked story arcs for a few characters. Mortal Kombat vs. DC Universe also contains a mode called "Kombo Challenge", where players must perform ten pre-created combos of increasing difficulty.
At the beginning of the game, both the Earthrealm of Mortal Kombat and the planet Earth in the DC Universe are being attacked by evil forces. At the same time, both attacks are repelled, sending super villains Shao Kahn and Darkseid into a state of dimension-shifting. This forces both villains, as well as their respective worlds, to collide into one, resulting in a mega-villain called Dark Khan. In order to defeat Dark Khan and separate their worlds safely, the heroes of both universes attempt to form an uneasy alliance. 2b1af7f3a8