The Shifty Scribe (Side Quest)
Find this quest in central Alexandria, north east of the Serapeion. A bereft wife needs you to rescue her husband.
Head to search area, and use Senu to ID the cart.
It's in theory guarded by several horsemen, but they tend to get lost easily. The cart itself is just going in circles, so the easiest way to secure Aristo is to snipe the cart-driver from the rooftops. The Predator Bow special skill can be extremely helpful here, though Aristo does seem to be immune to friendly fire.
When the cart is stopped, you'll have to carry Aristo to safety. This is the point at which the horsemen are most likely to find their way back, so be ready to either sneak fast or fight them off.
When the coast is clear, carry Aristo to the boat, and set him down.
Finishing this conversation completes the mission.