Full Synchronisation Requirement - Use your Assassin Signal at least once.
This is the first (and therefore compulsory) Master Assassin mission. These Memories mark the progression of your student Assassins to Master status, and allow them to protect your dens from Templar attack. More on this later, for now, follow your apprentice and listen to their concerns. When prompted, head to the meeting point to see if you can confirm your apprentice’s suspicions. You’ll have to take out three Templar guards at the objective marker, and you can do so in any way you see fit. Easiest is to take the nearest guard out quietly with the hidden blade or a ranged attack, meaning you can literally get the drop on the one on ground level in the square with an air assassinate. For the furthest away one, it’s a good opportunity to use your Assassin Signal to call in an apprentice assassin to take him out for you, earning you 100% Synchronisation when you finish the memory. With the guards taken care of, meet your apprentice at the hay cart.
After the exchange, you’ll have to investigate the area for evidence of a rogue assassin. Use Eagle Sense and examine the apparently peacefully sitting assassin on the bench to find that they were taken out by The Sentinel. Behind you you’ll be able to see a pool of blood too using Eagle Sense – move close to it and look at it for a second or two as you did with the body of the assassin to see a short scene from the past of another hit on a brother assassin.
With excellent dramatic timing, The Sentinel arrives and is identified by your apprentice as a fellow den member. Give chase until he eventually eludes you with the use of a smoke bomb, leaving you to contend with a few confused Templar guards. Take care of them in the usual way, with liberal use of counter attacks and executions preferably, and then walk with your apprentice again to finish the memory.