AMM: The Guardian, Part 2 - Assassin's Creed Revelations
Dealing with The Guardian
This one begins with the merchant telling you of his woes -- it seems that they are not cooperating with the Templar out of greed, but rather out of fear! You need to follow the merchant to the meeting with The Guardian -- and to attain 100% Synchronization you need to get to the meeting without being detected. Basically that means keep your distance.
When he meets the Templar the bloke is really cagey, so you will want to keep a little extra distance from him initially as he will stop and turn around to look back once shortly after they walk away. Follow them until they turn north and go through a security checkpoint, at which time you should run back into the street and into the courtyard east of the security checkpoint to reset the timer and trigger the CS.
The merchant will betray you -- and die for it at the hand of the Templar -- who then runs. You chase him down and kill him, ending the memory and scoring 100% Synchronization.
Confronting The Guardian