The satellite tracks Private First Class Joseph Allen. He has been reassigned to General Shepherd into the C.I.A. for an undercover assignment. The screen shows his new Russian tattoos.

PFC Allen: So how do I look?

Shepherd: Like one of the bad guys. Perfect for your undercover assignment.

PFC Allen: So Makarov is the prize.

Shepherd: Makarov's no prize. He's a whore. A mad-dog killer for the highest bidder.

Shepherd: Just remember your new identity. It'll keep you alive.

A Task Force 141 logo is shown.

Shepherd: Welcome to the 141. Best handpicked group of warriors on the planet.

PFC Allen: It's an honor. Sir, when do I meet the rest of the team?

Shepherd: They're on a mission recovering a downed ACS module behind enemy lines.

PFC Allen: Their feet wet?

Shepherd: Imagine they're just about freezing right now.

The satellite tracks Captain MacTavish and Sgt. Gary "Roach" Sanderson in the Tian Shan Mountains in Kazakhstan.

Tian Shan Range, Kazakhstan

Captain MacTavish and Sgt. Gary "Roach" Sanderson are sitting on the edge of a cliff in the Tian Shan Mountains, taking a break. MacTavish looks up as he smokes his cigar, a Russian MiG takes off from the top of the cliff. MacTavish smiles at Roach and tosses out his cigar.

Captain MacTavish: Break's over, Roach. Let's go.

Roach follows MacTavish as they climb around the wall of the cliff. MacTavish pulls out his ice picks.

Captain MacTavish: Stay here and spot me. Wait for my go.

MacTavish starts climbing.

Captain MacTavish: All right, the ice is good. Follow me.

Roach pulls out his ice picks and begins to climb, following MacTavish. As they climb, a MiG flies off, almost knocking MacTavish off the cliff. They continue to climb and make it to the top.

Captain MacTavish: Good luck, mate. I'll see you on the far side.

MacTavish runs and jumps off the edge of the cliff and makes it to the other side of the jump. Roach runs and takes the jump, barely makes it, and starts to slip.

Captain MacTavish: Hold on! Don't let go!

Roach holds on with one ice pick. He strains to hang on, but starts to fall. MacTavish slides down and grabs Roach's hand just in time. He then throws Roach up the wall. Roach continues to climb and makes it to the top. He pulls out his signature weapon: the new ACR (Adaptive Combat Rifle, an assault rifle), equipped with a Silencer, a Red Dot Sight, and the new heartbeat sensor attachment. MacTavish pulls out his new M14 EBR (Enhanced Battle Rifle, a sniper rifle), also equipped with a silencer and a heartbeat sensor. They climb up a path.

Captain MacTavish: Roach, check your heartbeat sensor.

Roach activates the heartbeat sensor, a small pulsing blue screen that shows a blue dot at the bottom.

Captain MacTavish: You should be able to see me on the scope. That blue dot is me. Any unrecognized contacts will show up as white dots.

They begin to move towards the Russian base. As they move along the path, the heartbeat sensor blips two white dots on the top of the screen when they approach a two-man patrol.

Captain MacTavish: Roach, these muppets have no idea we're here. Let's take this nice and slow. You take the one on the left. On three. One...Two...Three.

They shoot the two guards on "three" as a MiG lands on the runway.

Captain MacTavish: Nicely done.

If the player fails to kill the guard, MacTavish kills him for him.

Captain MacTavish: I guess I have to do everything myself?

If the player picks up an enemy weapon.

Captain MacTavish: Be careful about picking up enemy weapons, Roach. Any un-suppressed firearms will attract a lot of attention.

They continue on the path. The hearbeat snesor blips another two white dots when they approach another two-man patrol.

Captain MacTavish: Same plan. On three. One...Two...Three.

They shoot the two guards on "three."

Captain MacTavish: Nice work.

They continue on towards the base as a blizzard starts to pick up.

Captain MacTavish: The storm's brewing up.

They enter the base.

Captain MacTavish: Let's split up. I'll use the thermal scope and provide overwatch from this ridge. Use the cover of the storm to enter the base. You'll be a ghost in this blizzard, so the guards won't see you until you're very close. Keep an eye on your heartbeat sensor. Good luck.

MacTavish climbs up on a ridge to provide sniper support while Roach sneaks through the base. Here, the player has the option to sneak past guards and patrols without firing a shot or he can take them out to make his job easier.

Captain MacTavish: Nice shot.; Not bad.; You got him.; etc.

Certain guards he approaches will be eliminated by MacTavish.

Captain MacTavish: He's mine.; I've got him.; I'll take this one.

If Roach kills them first.

Captain MacTavish: Then again, maybe not.; Nevermind.

Roach goes further into the base.

Captain MacTavish: Alright, I've tapped into their comms. Head southeast and plant your C4 at the fueling station. We may need to go to 'Plan B' if things go south.

A truck with armed personnel drives in from the distance.

Captain MacTavish: There's a truck coming! Stay out of sight.

Roach hides and avoids the truck. He continues to the runway.

Captain MacTavish: Roach, the fueling station is near the northeast corner of the runway.

Roach continues towards the fueling station. If the player takes a while, the truck Roach hid from earlier drives by. Roach again hides.

Captain MacTavish: The truck is coming back.

Roach walks onto the runway.

Captain MacTavish: Hold up. I'm seeing some activity on the runway. Looks like twenty plus foot-mobiles heading your way.

Again, the truck Roach hid from drives by if the player takes a while.

Captain MacTavish: The truck is coming back.

Roach waits, and when the truck is gone, he approaches the fueling station.

Captain MacTavish: That's the fueling station. You found it.

Roach plants the C4 on one of the fuel tanks. If the player does so without killing or alerting any guards...

Captain MacTavish: No kills. No alerts. Impressive, Roach.

If done for the first time, the player earns the "Ghost" Achievement ("Sneak through the base without killing or alerting any guards in 'Cliffhanger'); Xbox 360 and PS3 consoles only.

Captain MacTavish: I'm picking up more radio traffic about the satellite. Standby. Got it. Sounds like the satellite's in the far hangar. Race you there. Oscar Mike. Out.

If the player takes a while to meet MacTavish.

Captain MacTavish: Roach, I'm waiting behind the hangers in the southwest corner of the runway.

Roach leaves the fueling station and the runway and moves toward the hangar with the ACS module inside. If the player moves towards the tower.

Captain MacTavish: Picking up large heat signatures near the tower, could be BMPs. I'd avoid that area.

Roach runs around the back of the hanger where MacTavish is waiting.

Captain MacTavish: Took the scenic route, eh?

If the player is taking heavy fire.

Captain MacTavish: Brought some friends with you?

Roach approaches the door.

Captain MacTavish: Let's go.

MacTavish opens the door, and down the hallway is a single guard. He runs at the guard, throws him against the lockers, then to the floor, and then stabs him. They walk into the hanger where the downed ACS satellite is seen partially disassembled.

Captain MacTavish: Go upstairs and look for the ACS module.

While MacTavish tries to open up the satellite, Roach runs up the stairs and enters a room with a computer with the ACS module on the desk next to it. When he picks it up, a loud clang is heard outside.

Captain MacTavish: Roach, I've been compromised! Keep a low profile and hold your fire.

Roach walks out of the room and sees MacTavish surrounded by Russians in the hanger.

Major Petrov: This is Major Petrov! Come out with your hands up! To enemy infiltrators, we have captured one of your comrades! You have five seconds to comply!

Captain MacTavish: Roach, go to Plan B.

Roach pulls out the detonator.

Major Petrov: Five! Four! Three! Two! One!

If the player does not detonate, MacTavish will be executed on "Zero!". Roach detonates the C4 at the fueling station. The explosion distracts the guards while he and MacTavish to kill them.

Captain MacTavish: Stay close and hug the wall! We'll use the MiGs for cover and cross the tarmac to the southeast!

Roach runs down the stairs and begins to take out the guards that are attacking from the runway.

Captain MacTavish: Roach! Follow me! Let's go!

Roach follows MacTavish out of the hanger and onto the runway.

Captain MacTavish: Head for that MiG, I'll cover you!

The MiG Roach is supposed to go to explodes.

Captain MacTavish: To the east, Roach! Go!

Roach heads east as vehicles explode on the runway. Snowmobiles appear.

Captain MacTavish: Snowmobiles! Take 'em out!

Roach kills the guards on snowmobiles.

Captain MacTavish: I'll cover you! Come to me!

Roach runs to MacTavish as he kills more guards on the runway.

Captain MacTavish: To the east, Roach! Go! I'll make a run for the next MiG! Give me some covering fire!

Roach covers MacTavish as he runs for the destroyed MiG. He also takes out guards coming out of a guard house.

Captain MacTavish: I've got you covered, Roach! Move up! Move up!

Roach runs to the end of the road.

Captain MacTavish: All right, let's go!

They slide down a hill. Guards run to the top of the hill, where they fire down on Roach and MacTavish. They kill the guards standing on the hill. Snowmobiles drive down the hill and begin firing on Roach and MacTavish. MacTavish stands behind a cabin and uses his ice picks to kill the guards on a snowmobile. Roach kills the guards on the other snowmobile.

Captain MacTavish: Roach, take that snowmobile! Let's get the hell out of here!

Roach boards the snowmobile and drives down the hill towards the extraction point, 2,300 meters away.

Captain MacTavish: Kilo Six-One, the primary exfil point is compromised! We're en route to the backup LZ using enemy transport! Meet us there! Over!

Helicopter Pilot: Bravo Six, this is Kilo Six-One, roger that, out.

Captain MacTavish: More tangos to the rear! Just outrun them! Go! Go!

As they drive, enemies on snowmobiles drive by. Roach takes out a G18 machine pistol and fires at them. A chase ensues through the mountains.

Captain MacTavish: Don't slow down! Keep moving or your dead! Go! Go! Go!

They drive up a hill.

Captain MacTavish: Come on! Come on!

They drive over a frozen lake, encountering more enemies and a helicopter. They drive up another hill and down a very long and steep downhill.

Helicopter Pilot: Bravo Six, we're at bingo fuel. What's your status, over?

Captain MacTavish: Kilo Six-One, we're taking heavy fire but we're almost there! Standby! (At Roach) Pin the throttle! Keep going!

They make a large jump from one side of a cliff to another, with the helicopter on the other side.

Captain MacTavish: There's the chopper! Let's go!

Helicopter Pilot: Bravo Six we have you on visual. Get your ass on board! We're running on fumes here!

Crew Chief: Okay, they got the ACS! We're outta here!

Roach and MacTavish board the helicopter.