Spoilers: (Highlight to reveal)
The opening intro is the final battle during the first tournament. The Earth heroes all fighting the bad guys. As Liu Kang is fighting Shang Tsung, Kung Lao makes a surprise appearence to save the day and starts fighting Baraka. Ultimately, Liu beats Shang and the bad guys retreat into the portal to Outworld as the island starts crumbling to pieces.

At the start of the game we find our heroes Liu Kang and Kung Lao making a desperate dash to escape Shang Tsung's slowly-crumbling island. Along the way they fight a bunch of Oni and bump into Reptile...who in the intro jumped into Outworld with the other bad guys....before finally finding a way back to the Shaolin Temple.

Back at the Temple, Raiden presents all our heroes with medals and congratulates them on their victory while Kung Lao grumbles about Liu Kang winning the tournament...feeling he should have won. Suddenly the Temple is under attack by an army of Tarkatans and our heroes spring into action. During the battle Sonya is captured by Baraka and taken to Outworld for some reason. Also, Shang Tsung and Raiden get into a fight, but we don't find out who wins. Meanwhile, Liu, Kung Lao, and Johnny Cage drive off the Tarkatans and put out a bunch of fires. And Kung Lao bitches about the battle.

Liu and Kung Lao then decide to stop and have a quick sparring match as Shang Tsung secretly looks on. Suddenly Raiden appears and demands "Do you trust me?"
Subtle.
As Liu and Kung Lao continue sparring, "Raiden" explains how Shang Tsung is up to no good and they should go into Outworld to figure out what's going on. Our heroes agree and head off to Outworld, with Johnny Cage secretly following.

Upon entering Outworld, Raiden tells them the realm is a crazy place and they should watch out. Raiden then gives them vague insructions about finding allies and disappears. Liu and Kung Lao proceed to wander around until they stumble upon the Evil Monestary where a woman proclaims she is the Princess of Outworld in a very hammy manner. Raiden then appears and tells them to find Kitana, 'cause she will help them in their vaguely-defined quest.

Liu and Kung Lao follow Kitana up the tower as she shouts cheesey threats to them like a 60's cartoon villain. They finally catch up to her and she immediaty attacks them. And Liu's response to this attack?
"You're beautiful."
Kitana proclaims she is going to kill them and Kung Lao grumbles about she's supposed to help them. After a brief fight, Kitana runs off and Raiden appears revealling she's under a spell. Our heroes then follow Kitana where she gets caught in some bizarre device which...as luck would have it...can break her spell. *Whew*

But Jade and Mileena appear on the scene and get Kitana out of there. Our heroes fight the three assassins, managing to toss Kitana in the magic-spell-breaking-gargoyle-thing. She is freed and we are treated to Liu Kang dramatically catching a fainting Kitana in slow motion. Our heroes then go on to fight and defeat Jade and Mileena, showing their sadistic side by stabbing Jade in the face with Mileena's sais.....'cause that's what Shaolin Monks do.

Kitana wakes up and thanks our heroes for freeing her. But her good mood is cut short upon discovering Jade's dead body, to which she naturally gets mad at our heroes.
"She was my best friend and you killed her!"
"So what you're saying is we should've stabbed the other one in the face..? Whoops."
Our heroes interrogate Mileena who snarls about her and Jade keeping Kitana under a spell. Kitana then mentions how it is really Shao Kahn who is trying to take over Earth...which confuses Liu and Kung Lao because they don't know who that is.....which seems odd 'cause one would think Raiden would've mentioned that in the first tournament. Kitana then suspects Reptile may be near....which again confuses Liu and Kung Lao even though they have met Reptile.

Mileena uses this oppurtunity to escape and Kitana gives chase, declaring she cannot allow Mileena to escape. After they disappear, Kung Lao suspects there's more going on than they think, but Liu dismisses his suspicions, confident Raiden would tell them.

Liu and Kung Lao start to head back and Raiden appears, telling our heroes that Shang Tsung has used his magic to......somehow connect his power to Outworld and it's warriors so the more Liu and Kung Lao win fights the weaker he gets.....or something. Liu then suggests this would put them in competition....even though it doesn't...and Raiden says it must be done and sends them off to...wander around and get into fights.

Our heroes return to the portals and catch a glimpse of Reptile. Remembering that Kitana mentioned him, Kung Lao suggests they follow and our heroes head off into the Living Forest to find Reptile.....to weaken Shang Tsung, and so he can maybe lead them to Kitana. Our heroes track Reptile to his lair and proceed to brutally kill him without bothering to ask where Kitana is. Guess they forgot.

After murdering Reptile, Raiden appears and congratulates them on killing Reptile, saying they are feeding the Soul Tombs and this is good. Kung Lao queries how this is supposed to help save Earth, but Liu cuts him off and thanks Raiden for his praise. After Raiden disappears, Kung Lao wonders why Liu cut him off and Liu reassures him Raiden will tell them what they need to know....further reinforcing that Liu will blindly believe anything Raiden says.

As our heroes exit Reptile's Lair, Raiden appears again and tells them to destroy the Soul Tombs, for they are the source of Shang Tsung's power.....even though a few seconds ago he said feeding the Soul Tombs was a good thing. Neither Liu Kang nor Kung Lao seem to notice. Raiden takes Liu aside and warns him the realm may be getting to Kung Lao....and that the Soul Tombs are the source of Shang Tsung's power. Later, Raiden takes Kung Lao aside and tells him to trust his instincts....and that the Soul Tombs are the source of Shang Tsung's power.

When our heroes finally get out of the Living Forest, Raiden appears again and reveals that by killing Outworld's warriors they are feeding the Soul Tombs...which are the source of Shang Tsung's power....even though earlier he said Liu and Kung Lao defeating Outworld warriors would weaken Shang Tsung. Kung Lao then wonders what they're supposed to do and Raiden sends them off to destroy the Soul Tombs.

Our heroes head off to the Soul Tombs, but are too late to stop Shang Tsung from regaining his youth. Tsung then proceeds to kick our heroes' asses...but doesn't kill them, declaring they aren't worthy additions to his power. Our heroes recover and destroy the Soul Tomb. Did that weaken Shang Tsung? Was that part of his plan? Was sparing their lives part of his plan? And if so, in what way?
Who knows.

Moving on, our heroes stumble upon Baraka torturing some Shaolin Monks. After stabbing one in the face, Liu wonders if he is all right. Our heroes then fight and defeat Baraka who is torn apart by vengeful souls. Liu and Kung Lao then witness a bizarre vision of their ancestors fighting over who won the Mortal Kombat tournament. Kung Lao wonders what the purpose of that vision was and Liu says he doesn't know...but is confident there was a purpose.

After leaving the Soul Tombs, our heroes stumble on Kitana and Mileena fighting. Mileena then runs off to the Wastelands to, according to Kitana, seek help from Goro in destroying her and later Liu and Kung Lao. Kitana yells them a bit, then explains Mileena's origin and runs off to chase her. Liu declares they cannot allow Mileena to kill her and they rush off to the Wasteland. So we're back to sort of helping Kitana again.

Shortly after getting into the Wastleand, our heroes are attacked by Sub-Zero, who immediatly jumps to the conclusion that they are enemies. They fight and Sub-Zero is scarred by Kung Lao which makes Liu stop the fight, revealling Raiden told them Sub-Zero was dead. Sub-Zero then reveals he is the original Sub-Zero's brother and he is in Outworld to find/avenge him.

Liu then explains how they're trying to stop Goro to help Kitana. Sub-Zero, despite never meeting Kitana and knowing nothing about her, immediatly jumps to the conclusion she is no match for Goro and decides to help them. Our heroes and Sub-Zero fight their way to some dilapidated palace, but Sub-Zero is sidetracked by Scorpion who appears for a second, then immediatly scurries off. Sub-Zero follows Scorpion, determined to avenge his brother.

Liu and Kung Lao find Goro who storms around like he is the king of the universe and Kung Lao complains that Sub-Zero said he'd take care of Goro. Our heroes defeat Goro and Johnny Cage pops up and finishes Goro off for a quick laugh. Liu then starts bitching about Cage stealing his kill and then attacks Kung Lao. But Cage proves too slick for that and reveals it's really Shang Tsung. The real Liu shows up....he and Kung Lao were apparently somehow separated during the battle with Goro....but Kung Lao isn't happy.

Johnny Cage tells our heroes how he's been on to Shang Tsung the whole time. Raiden appears and says he has a mission for Cage and they walk off. Liu and Kung Lao leave the Wasteland only to be sent by Raiden into the Netherealm. Why? Because going to the Netherealm will help them defeat Shang Tsung. In what way? Who knows.

So our heroes head off into the Netherealm and stumble across Sub-Zero fighting Noob Saibot, whom Sub-Zero suspects may be his older brother. Sub-Zero then warns Liu and Kung Lao that Scorpion wants to kill them. Why? Because it's Scorpion. Our heroes pay no mind and find Scorpion and fight him. They defeat him and he acknowledges their victory with a thumbs up.

With Scorpion defeated, our heroes leave the Netherealm to find Raiden who declares they are ready to fight Shang Tsung. Raiden then secretly tells Liu that Kung Lao is somehow different. Liu suspects Shang Tsung may be posing as Kung Lao and Raiden tells him to be careful.

Our heroes head down to the Foundry where they bump into Jax who claims Raiden's been helping him wander around Outworld, which makes Kung Lao suspicious. After fighting through the Foundry, they end up at Shao Kahn's collessium where they find Johnny Cage and Kitana have been captured....guess Cage wasn't on to Shang Tsung after all. Kung Lao mentions he doesn't trust Raiden and Liu attacks. They fight a bit but Raiden appears and starts yelling at them. Before he can say anything else, he is suddenly blasted by Shao Kahn who pretty much says "If you want to know what's up, follow me."

Our heroes follow Kahn and Raiden suddenly appears again and attacks them. Even though Shang Tsung has already posed as just about everyone else, it never occurs to Liu that he may be posing as Raiden. Sure enough, Shang reveals he's been deceiving them this whole time and using them for his plans. They then start fighting and Shang loses and dies. Well done, Shang.

Shao Kahn then reveals Tsung was using them to kill Outworld warriors so he could get stronger and overthrow him. But by killing Tsung, Liu and Kung Lao have served his purposes. Kahn then decides to have them killed and calls out Kintaro. But Kintaro fares no better than Shang Tsung and is torn apart by our heroes.

Meanwhile, the real Raiden has freed Johnny Cage and Kitana. In spite of this, and Liu Kang and Kung Lao killing every other one of his warriors, Shao Kahn proclaims he will soon conquer the Earth, to which Kung Lao bizarrly replies "It's about time."

Our heroes then fight Shao Kahn and emerge victorious. Raiden turns Kahn to stone and Liu and Kung Lao shatter him to pieces to the cheers of Outworld. Liu and Kung Lao are suddenly best friends and pat each other on the back for winning. Then...despite she being an ice-queen bitch the whole game and he denying he likes her as if he's in the 2nd grade...Liu and Kitana start flirting.
"I meant about us?"
"Whoever said anything about an 'us'........you killed my best friend dick."

Raiden then gives a happy speech about how Liu Kang and Kung Lao have overcome the comflicts of their ancestors and learned to work together. Our heroes then walk off into the sunset.....unaware that Quan Chi has found some sort of amulet from Shao Kahn's remains. We don't know what amulet that really is or what it does...but Quan Chi is happy to have it...which could only mean bad news for our slow-witted heroes.

The End....or is it..?