This (downloadable add-on) sequence requires that you retrieve the Da Vinci Painting without being spotted by the Robed Disciples. The first part is simple: you just need to climb on the rooftops and head in the general direction of the green point on the map. If you see any guards, you're welcome to dispatch them, but ignoring them works just as well. You can be detected by guards and still get %100 Synchronization. After reaching the area where the minimap becomes green, perform a Leap of Faith off the rooftops (assuming your still on it) and run towards the river. If you can't find your target, activate eagle vision. He will appear in yellow. After beating up the merchant and his minions, head over to the ship with the robed disciples. Get just close enough to the ship to highlight one of the disciples, then, assuming you have the arrow storm available to you, press and hold left bumper to activate it. This will eliminate all of them, paving an unimpeded path to grab the painting.