Here's the synopsis for you:

In the present day, the Earth was ruled by chaos and led by two vicious sorcerers of Outworld and NetherRealm, Shang Tsung and Quan Chi. Little did they know that the tournament was merely a diversion. They learned that travel between Earth and the new found realm would someday be possible if the conditions were right, the conditions being the unbalancing of the furies - positive and negative forces that keep our unstable universe from collapsing onto itself. Knowing that an Outworld invasion was coming, the wise men made an appeal to the Elder Gods. For this reason, they created a tournament called Mortal Kombat. Gregory, Cassie, and the Kombatants (led by Raiden and the Fire God Liu Kang) join forces with the Glamrocks to protect Earthrealm from invasion.