Security Detail is the tenth level of Call of Duty: 9. The player controls Sgt. William Thomas as he and Hanover are sent as a security detail to the British Parliament Building when a Titanium product is sent there.
Hanover and Thomas are walking along with other guards with Prime Minister Kevin Doyle as he welcomes the Titanium Shipping representative. The rep. remarks that the shipment should be here now, and a truck crashes through the wall. The rep. aims at Doyle, but Thomas throws a leg of a chair at him, and shoots him. The team then takes out soldiers comes out of the truck. As Pvt. McLean asks Doyle if he is okay, Hanover remarks they need to get him out of there. They clear out a couple of rooms, but the floor collapses, so they run on a ledge. A rocket nearly hits them, so Thomas picks up an RSASS and kills the RPG troopers. They get back inside the buildings, and clear a stairwell. When they get to the bottom, they throw the president behind a counter, and shoot incoming enemies. Another security team comes there, and they tell Hanover and Thomas they need to get the other governors. The two fight to another staircase, and clear their way upstairs.
The two fight through several hallways and rooms. They then breach the governor's room, and shoot all the soldiers inside. As they secure the governors, a helicopter bursts through the room, knocking everybody down. Thw helicopter slides a bit, and reveals lots of soldiers coming towards them. Thomas gets on the heli's machine gun and shoots at the incoming enemies. A BMP shoots the helicopter, causing it to fall out of the building. Thomas gets off the ground and Hanover tells him to regroup with him in the conference room. Thomas picks up a MP5 and fights through enemies. A BTR rolls in front a hole to the conference room, so Thomas lays a smoke screen, and jumps over the BTR and into the conference room. As the BTR turns around, Hanover gives Thomas C4 which he plants on the BTR. The explosion causes the wall the collapse, so the group runs out of the room before it all is buried. They fight to a friendly convoy carrying out governors. Thomas protects the convoy until is rolls away. The two then get onto a helicopter, where they are lifted into the air.