From New York, head out into the Frontier and make your way back to Washington's fort. Talk to him again and Haytham will be sure to cast Washington in a bad light. After you find out what is happening, you'll have to try and save your village. Hop on a horse and ride out of the fort.
There will be a few messengers along the path ahead of you and you need to find them so you can prevent the attack on your village. Whenever you get the chance, be sure the spur your hors so you can get that little bit of extra speed. Follow the green marked path on your radar until you find your first target on the road. This first target seems to have been knocked off his horse. Since you can't touch the ground, shoot him to kill him.
Continue along the road and you'll come along a group of three messengers riding single file on horseback. Come up behind them and hit the attack button to jump off your horse and assassinate the rider closest to you. You will take his horse. From here, quickly do the same thing to the second guy to leave only one. This last man will have a chance to escape so he'll be a little harder. You can try and get close to perform another assassination or you can shoot him to be on the safe side. Either choice is acceptable.
With this next band of messengers killed, keep riding to find the last messenger. Eventually, you will come along him riding by himself along the road. He will be more cautious and almost immediately notice you so try to close the gap by spurring your horse so you can attack him or simply shoot him when you have a clean shot. If you manage to kill him before the timer runs out, you'll have completed one of the constraints.
Ride further along the road and off the right side, you'll see a restricted area with a lot of soldiers. Avoid them at all costs and make your way along this path. When you get the chance, turn right and make your way safely to your village. Enter the village on horseback and ride up to the Clan Mother to talk to her.
She will tell you that some of the villagers have set out to stop the attack on the village. Make your way into the valley where you played as a child. Make sure that you have no weapon equipped by using the D-Pad and then come up behind any of the red marked villagers. If you sneak up on them, you can take them down without killing them. This will take longer than an assassination so if they happen to be with another villager, you will have to fight the second villager. When they attack, throw them and then attack them to take them out. Be careful if you disarm them because you will then be wielding their weapon which can kill them if used against them.
Take out the six marked targets and you will have to confront your friend.
