When you arrive in London you'll be introduced to the man you're here to protect, Mr Brown. You can urge him to call off the event, but he's pretty determined to go ahead with it anyway and feels he's made all the precautions required to prevent any sort of terror attack against it. When the conversation is done, you'll be tasked with meeting his head of security downstairs.
Step 1)Meet Liam Slater in the C.S.O.
Take the elevator down to the C.S.O level and just head straight ahead to speak with a security guard. Something seems off with this guy, and the other guys flanking you don't look any friendlier. They aren't about to let you in to see Chief Slater. It's up to you on how you want to handle them, but with one of them behind what I assume is bullet proof glass, you can opt to trick them for that guy to wander off, supposedly to tell the chief you're here personally. You're not about to wait for him to do that though, it's time to put those stealth skills to the test and break in to see what's going on. You can try to storm in past the turrets, laser grids, and guards if you like, but if you look to the left of where the guard was, there's a keypad you can hack to gain access without going through that. Head to the left and up the stairs, past the second laser grid, and through the tough security door to find some dead Tarvos security guards. Uh oh.
Step 2)Get to Liam Slater's office.
Mac and his team were on their way to provide backup, but they've been stopped by security doors they can't bypass. It's up to you to get to Liam's office where there should be an override for the doors, so continue on through this room of dead guards. Slip past the camera in the next room by sticking to the right, and if you follow close enough behind the guards when they split up you can follow this guy right through the laser grid before you knock him out. Watch out for the turret in the corner and head through the double doors here to find Liam Slater's office. Flip the switch to bypass the security doors.
Step 3)Find the keycard to catering.
It looks like the whole place has been compromised, and gold masked terrorists are crawling everywhere. Miller wants you to do this quietly or all hell is going to break loose though. First, you're going to need to get access to catering. Drop down through the vent system to bypass another laser grid and slip past the camera and the guard into the little security office. You can turn off the windows here so you can take the guard here out without being spotted. Proceed out the back door of this office and into the ventilation system right across from the door, then stick to the windows and sneak through the hallway at the top of the stairs here to get into a second ventilation shaft, which will in turn lead to a third. This will exit out into a security office with a terminal right in front of you, but before you touch it, head towards the window to turn off the visibility. Hack the computer and you can turn off cameras, robots, alarms, and laser grids. This is going to make things a lot easier for you going forward. Slip out of this room and make your way to the elevator. This little area isn't restricted, so don't worry about the patrolling guard and head down to reception. The guard you are looking for is on the very bottom level, an older guy. If you hide behind a couch he'll come chat with the other guard stationed in front of the couch and then head into the washroom. Take him out and grab the keycard.
Optional Step 4)Discreetly eliminate all 11 guards.
Once you've gotten the keycard, you can try to continue on to your next mission, but you'll have to pass by the guards and they will alert Marchenko, starting missions 16 and 17 at the same time, as well as any of the guards standing will be hostile towards you and come after you. It's best to take them out, but the same will also happen if you are seen taking them out. Do your best at this point, and save after each guard you take off in a new save slot. Make sure to hide the bodies as you go and eventually you'll manage to work your way through them all and be able to continue on towards the final confrontation.
Step 5)Find Miller.
If you decide to take the guards out quietly, or things get a little loud, you'll move on past the party itself to the next area. This hallway has two guards, one on patrol and one stationary. Get past them to the kitchen and you'll find Miller has been incapacitated trying to stop the terrorists.
At this point, you'll be given a choice to either save Brown and the delegates, or try to deactivate the bombs in the residential towers. If you choose to save Brown, move on to mission number 17, but if you choose to stop the bombs move on to mission 16.
Step 1)Meet Liam Slater in the C.S.O.
Take the elevator down to the C.S.O level and just head straight ahead to speak with a security guard. Something seems off with this guy, and the other guys flanking you don't look any friendlier. They aren't about to let you in to see Chief Slater. It's up to you on how you want to handle them, but with one of them behind what I assume is bullet proof glass, you can opt to trick them for that guy to wander off, supposedly to tell the chief you're here personally. You're not about to wait for him to do that though, it's time to put those stealth skills to the test and break in to see what's going on. You can try to storm in past the turrets, laser grids, and guards if you like, but if you look to the left of where the guard was, there's a keypad you can hack to gain access without going through that. Head to the left and up the stairs, past the second laser grid, and through the tough security door to find some dead Tarvos security guards. Uh oh.
Step 2)Get to Liam Slater's office.
Mac and his team were on their way to provide backup, but they've been stopped by security doors they can't bypass. It's up to you to get to Liam's office where there should be an override for the doors, so continue on through this room of dead guards. Slip past the camera in the next room by sticking to the right, and if you follow close enough behind the guards when they split up you can follow this guy right through the laser grid before you knock him out. Watch out for the turret in the corner and head through the double doors here to find Liam Slater's office. Flip the switch to bypass the security doors.
Step 3)Find the keycard to catering.
It looks like the whole place has been compromised, and gold masked terrorists are crawling everywhere. Miller wants you to do this quietly or all hell is going to break loose though. First, you're going to need to get access to catering. Drop down through the vent system to bypass another laser grid and slip past the camera and the guard into the little security office. You can turn off the windows here so you can take the guard here out without being spotted. Proceed out the back door of this office and into the ventilation system right across from the door, then stick to the windows and sneak through the hallway at the top of the stairs here to get into a second ventilation shaft, which will in turn lead to a third. This will exit out into a security office with a terminal right in front of you, but before you touch it, head towards the window to turn off the visibility. Hack the computer and you can turn off cameras, robots, alarms, and laser grids. This is going to make things a lot easier for you going forward. Slip out of this room and make your way to the elevator. This little area isn't restricted, so don't worry about the patrolling guard and head down to reception. The guard you are looking for is on the very bottom level, an older guy. If you hide behind a couch he'll come chat with the other guard stationed in front of the couch and then head into the washroom. Take him out and grab the keycard.
Optional Step 4)Discreetly eliminate all 11 guards.
Once you've gotten the keycard, you can try to continue on to your next mission, but you'll have to pass by the guards and they will alert Marchenko, starting missions 16 and 17 at the same time, as well as any of the guards standing will be hostile towards you and come after you. It's best to take them out, but the same will also happen if you are seen taking them out. Do your best at this point, and save after each guard you take off in a new save slot. Make sure to hide the bodies as you go and eventually you'll manage to work your way through them all and be able to continue on towards the final confrontation.
Step 5)Find Miller.
If you decide to take the guards out quietly, or things get a little loud, you'll move on past the party itself to the next area. This hallway has two guards, one on patrol and one stationary. Get past them to the kitchen and you'll find Miller has been incapacitated trying to stop the terrorists.
At this point, you'll be given a choice to either save Brown and the delegates, or try to deactivate the bombs in the residential towers. If you choose to save Brown, move on to mission number 17, but if you choose to stop the bombs move on to mission 16.