Full Synchronisation Requirement - Perform a zipline assassination.
This memory introduces one of the new features in Assassin’s Creed: Revelations - ziplines.
Follow Yusuf onto the rooftops, and do as he does - leap onto the zipline as you would normally jump onto a ledge. You can control your movement speed by pressing the high profile button or letting it go, speeding up and slowing down respectively. Keep an eye out again for more Animus Data Fragments as you go.
When Yusuf takes out the first Templar scout with a zipline assassination, wait until the remaining one has moved over to examine the body following Yusuf’s poor acting, and then slide down the zipline. When you near the Templar, the option to assassinate him should appear. Press the button to take him out, then climb onto the roof to regroup with Yusuf. After your discussion, he will send you to reinforce the defence of the Galata Den. Move across the rooftops to the objective marker to end the Memory and get your first taste of the Den Defence minigame.