Suggested Level: 6
£: 600
Infiltrate HQ
Head south away from Churchill’s HQ toward the marker on your map. The entrance to the HQ building is on the bottom floor of the east side of the building.
Once inside, head upstairs and pick the lock of the door to the right. Using your Eagle Vision, follow the footsteps toward a suspicious bookcase. Examine the bookcase to reveal the entrance to the secret spy HQ.
Kill the Spies
After gaining entry, you need to kill four spies. Shoot one with a hallucinogenic dart, then pick off the rest with throwing knives while they attempt to fight the hallucinating spy.
Kill the Master Spy
With four spies dead, your focus shifts to the Master Spy. You have a short fight with him in the room, however he uses a device to stun you and then escapes out the window.
Locate the Master Spy
Chase the Master Spy through the streets. There is no need to stop and fight the enemies that you encounter along the way, just be ready to press 
/ 
to counter their ranged attacks as you run. Keep your smoke bombs equipped to quickly get through the enemies that try to slow your chase on the target before eventually cornering him in a courtyard.
There are a large amount of enemies nearby. However, most of them will be fighting Rooks so they do not pose much of a threat. Focus your attacks on the Master Spy. Throw a smoke bomb down on the ground before attacking to disorient any enemies around you.
Once the Master Spy is dead, flee the area. You do not need to kill the remaining enemies for completion. If you flee to the north, you can climb up and over the building before jumping in the water and swimming to safety.