Three super-large prison ships loaded with dissidents exiled from Earth in the 22nd century crash landed into Moria, Umoja, and Tarsonis where an oppressive government the Confederacy was established. Years after the Guild Wars between the Confederates and the Kel-Morians (people from the planet Moria), a fleet of vessels belonging to an alien humanoid race, the Protoss, incinerated the human colony of Chau Sara.
The portal took Matthew to the neighboring planet, Mar Sara, and he became lost, "where am I?" The engineer was found by a man riding a Vulture hover bike and he introduced himself offering a handshake, "Hi, my name is Jim Raynor, welcome to Mar Sara, it's nice to meet you." "I'm Matthew Turkins, it's nice to meet you too," Matthew shook hands with the man.
"I don't think it is the right place for chatting here. We're going back to base," Raynor took Matthew to a military base, where he received training in the barracks to become a general purpose marine. Despite Raynor was a marshal, he was Matthew's mentor due to his previous experience as a marine in the Guild Wars. Matthew revealed to him that he was an engineer; however it required him to take months of brutal training ranging from physical exercises to handling a gun for months. He had to wear a powered suit of armor for combat. At the same time, Matthew took the time to research the technology and current troops.
Raynor was called to a meeting with the magistrate who allowed Raynor to lead the marines to help out in solving the problem in Backwater Station. It was Matthew's first time in combat and Raynor ordered him to defend the base. Matthew saw was a strange-looking human that appeared to be mutated and with claws protruding from his shoulder. "Please kill me," muttered the strange man that the engineer assumed to be infested. Matthew fired his C-14 gauss rifle pelting the mutant with armor-piercing spikes from the U238 shells. Those bullets in fact deal extra damage to light armored and unarmored opponents. He found that it was easy to take on those infested humans and considered it as it was a game. Hours later, no more infested were coming but Raynor had not returned.
He quietly sneaked into the magistrate's office asked about Raynor's whereabouts. "Those damn Confederates arrested Raynor and his men for destroying the infested base that the Confederates considered as their vital installation," answered the magistrate.
"Infested? What's going on?"
"This world is now under attack from the Zerg and they infested a base not far from Backwater Station by planting a Virophage. What you fought were infested humans," explained the magistrate.
"What's a virophage?" Matthew had never seen this kind of structure from the multiplayer games. He knew the Zerg only as a race of alien insects.
"A virophage is structure belonged to the Zerg used for infestation. What Jim did was right as we cannot wait for the Confederate reinforcements to come. Now they are withdrawing," the magistrate was at ease.
He was later received a transmission from another contact, "Good day, Magistrate. My name is Arcturus Mengsk, and I represent The Sons of Korhal. You're familiar with the Confederate propaganda surrounding my group, but your reputation suggests you'll see past it. It's never been our practice to operate in any one place for long, but these Zerg don't look like they're going to wait. I'm going to make you an offer, Magistrate. I'd like to help you out by sending down a number of transports to your colony and evacuating any survivors.
You know, of course, that my organization operates outside the bounds of Confederate law. That's why they spread their lies and misinformation. If you decide to accept our help, you'll be branded as an outlaw too. But, it's a chance to save those people. Time to make a stand, Magistrate."
"We'll accept your offer for the well-being of the people," the magistrate agreed to take such risk and turned to Matthew, "I need you to take part in the defenses".
The magistrate's current forces consisted of medium-armored marines, medium-armored medics as support troopers that provided medical treatment to the wounded, fortified-armored Firebats wearing a more durable suit with full-face helmets and had flamethrowers suitable for roasting the Zerg as it could deal more damage against organic enemies besides extra damage against light armor and the unarmored, and light-armored Vulture bikes with a piercing grenade launcher used for anti-infantry as well as destroying light-armored vehicles.
Besides the defense, Matthew also needed to help safeguard the colonists and civilians from the Zerg. "We better take cover in those bunkers if things get a bit too dicey," a marine muttered as he and the other three marines entered the defensive structure with ammo supply and devices that enable marines inside the building to reach further enemies. The Vulture bikes also take the role of placing robotic Spider mines around the base besides scouting. With the troops positioned, an alarm was sounded as a swarm of Zerglings, fast light-armored dog-sized breed resembling a mix between a dog, a bug, and reptile. Zerglings were fast melee attackers with claws that could cut through anything and could inflict extra damage against medium armor. "Here they come, lock and load!" said a marine as Matthew and the soldiers repelled the first attackers. Matthew was scared for the first time when facing danger during combat; however he bravely shot a couple of Zerglings. Vulture bikes returned to the base with a squad of five marines. The next wave of Zerg attackers not only limited to Zerglings, but also included a couple of Hydralisks that had characteristics of serpents. The Hydralisks were medium-armored high-damage range attacker that fired piercing needle spines. After the second squad consisted of four marines and a medic were rescued, the Zerg launched an air strike with light-armored Mutalisks that had bat wings and an extra mouth in the tail ejecting piercing acidic Glave Wurms bouncing on three targets. Those Zerg flyers were countered easily by missile turrets whereas the marines including Matthew had to mind their aims to shoot them down. Following the air strike, the Zerg ground attackers added fortified-armored Roaches used as assault units that attack the ground forces at a distance with piercing acid saliva. After the last squad made up of five marines, a medic, and a pair of Firebats; the Zerg kept coming relentlessly.
Matthew and his troops held off the attackers long until the Sons of Korhal transports arrived in the form of Medivacs which were fortified in armor. Besides taking the role of aerial transport, they had laser scalpels installed to provide medical treatment to wounded infantry. They were escorted by Wraith fighters armed with piercing lasers and anti-air missiles with siege capability that inflict more damage against fortified armor and unarmored opponents. The fighters activated their cloaking devices to prevent the Hydralisks from shooting them down. Following the fighters and transports was a powerful Battlecruiser, a warship with fortified armor and equipped with powerful guns that fire lasers that deal full damage to all armor types making them capable of destroying anything. The incoming Zerg were burnt by the chaotic lasers and it was made easier to the defenders. Inside one of the Medivacs was Raynor, "Raynor, how did you…" asked Matthew. "I'll explain later, we got civilians to evacuate right now," the marshal cut him off. The duo assisted in the evacuation as the colonists were loaded into hundreds of Medivacs that Mengsk deployed.
After the evacuation; Raynor, Matthew, and the magistrate boarded the Battlecruiser named Hyperion that took the role as Mengsk's flagship. In the meeting, the magistrate was promoted commander and Raynor as captain. "Hey man. Arcturus' boys sprung me from the prison ship. Apparently, they're as frustrated with the Confederates as we are! I know their reputation, but they seem to be on the level. I think Arcturus wanted to speak with you..." Raynor spoke to the commander who receives the mission from Mengsk. "Commander, Mar Sara is almost completely overrun by the Zerg. The Confederates are abandoning the planet, and so are we. However, there is one thing I'd like to do before we leave. I want you to raid this colony's Confederate outpost and retrieve whatever design or weapons' schematics that you can find in their networks. With the chaos of the Confederates' evacuation, you shouldn't have any trouble getting in or out of their installation."
"I'm into it," Raynor decided to take part in the mission, but Matthew was not enthusiastic about it. However, Mengsk also sent the engineer along with Raynor for the operation. Matthew decided to give any enemy no mercy as he expected of receiving none in combat.
In Jacobs Installation, "Raynor, Turkins, hang tight for a sec when we clear the entrance," one marine told both heroes. "They locked the door, set the bomb!" the other marine placed the charge and detonated it killing the Confederate marines behind the door. The nine Sons of Korhal marines proceeded in cleaning out the marines guarding the doorway. "We're in, this room's clear," a marine gave the signal allowing the two Firebats, two medics, Raynor, and Matthew to enter. "Medic!" shouted a marine to get a medic to treat his wounds. When Raynor operated a control panel, they saw three more Confederate Firebats were moving into position along with five more marines via the security camera. "Hmmm, fry any rebel you see," the enemy Firebat muttered.
"Let's activate the gun turrets and use them as a distraction," Matthew came up with an idea.
"System accessing, decrypting computer override, system control established," the artificial intelligence spoke as she hacked the system.
"Now we get half the guns. I say the left," as Matthew hit the button. "Go!" the engineer quickly moved in with the others following him.
"What th…" the Confederate Firebat was surprised as three of the sentry guns fired at him and the other Firebats. The Sons of Korhal Firebat took the opportunity to incinerate the enemy marines while Raynor, Matthew, and the ally marines blasted the Confederate Firebats. The Firebats exploded when killed leaving fuel containers as remains and the sentry guns turned to the Confederate marines assisting the Sons of Korhal. When they reached a lab, a Confederate scientist shouted to the group, "Hey! You're not allowed in here!"
"Shut up or I will stick a bullet in your gut," Matthew pointed at him with his C-14 gauss rifle.
"Oh my god, don't kill me," the scientist scurried.
"Zerg! I don't believe this!" Raynor was shocked when a holding pen released Zerglings. The Sons of Korhal Firebats handled the melee attackers with ease.
"Believe it. I saw Zerg within Confederate holding pens myself, and that was over a year ago. It's clear the Confederates have known of these creatures for some time. For all we know they could be breeding the things! Be that as it may, our priority here is accessing the Confederate nework. We'll deal with the Zerg another day," Mengsk explained and reminded the task force.
The squad destroyed the holding pen and killing its occupants when doing so. In the next computer terminal, Raynor and Matthew spotted hover tanks that were unmanned. "If we could get over there, we can hijack those Diamondbacks," a Sons of Korhal marine spoke. When they arrived at the bay, the six marines quickly commandeered the six Diamondbacks as each of those fortified-armored vehicles had a one-man crew. Those hover tanks were armed with rail guns that had siege capability and could even fire when moving. The next cargo bay was full of heavier units manned by the Confederates themselves. The fortified-armored Goliath combat walkers were armed with 30 mm piercing autocannons and anti-air missiles of siege capability. The siege tanks' armor were tougher than the modern tanks in the real world and were equipped with twin 120 mm cannons that fired projectiles that could deal extra damage against fortified armor and unarmored enemies. The Diamondbacks could handle the Goliath combat walkers easily but the siege tanks were quite a challenge. The fuel barrels inside the cargo could help soften up the siege tanks and the infantry defending it. At the room where the main computer was located, there was a Confederate Ghost who wore the hostile environmental suit different from the marines and Firebat. He was equipped with a piercing 25 mm C-10 Canister rifle used for anti-infantry. Matthew gave the Ghost a headshot killing him instantly and then accessed the main computer taking everything from it. "You rebel scum!" muttered a scientist.
Raynor reported to Mengsk and the commander, "Hey, we've found the plans, man. Have the transports waiting when we come out." Raynor, Matthew, and the squad took the stolen data discs and got out to the transports waiting for them. The Sons of Korhal fled to the border colony of Antiga Prime where Arcturus' group now planned its next crucial moves against the Confederacy.
Thirteen hours after the evacuation of Mar Sara, Protoss warships took up orbit around the colony and unleashed a massive planetary bombardment.
All life upon the surface was extinguished.