The Templars know about the Assassin’s plans, but there currently isn’t much you can do about them. You have to find a way to get back the initiative and turn people against the brigands in New York.
Kill the Gang Members
Your first step in the plan is to get some nice uniforms to disguise yourself. Two criminals run past at the perfect time, and you have to follow them through New York. You can rush to join these criminals on their rooftop race, but a few good pistol shots end their run before it gets very far. Sprint after the criminals while arming and reloading your pistols, as needed.
When the men try to climb, they’ll be much easier targets. That’s your cue to fire! Get them both this way if you can.
Go up to the rooftops if this fails. Run after the targets while looking for an opening to shoot or tackle them. Once they’re down, you get a new goal.
Amusingly, you also get credit if anything else happens to the criminals. If they fall or get attacked by other enemies, you still get the job done.
Rob the Fort
Optional: Loot every chest (10)
Optional: Lockpick two doors
Now that you look like a proper criminal, go into the British fort and engage in some brigandage. There are five locked rooms inside the fort. Each one has two chests (colored blue on the map to let you know that they’re objectives).
There isn’t much time, but your goal is to get all 10 chests opened within four minutes. Don’t worry about the lockpicking goal, because that just helps you get the job done quietly. It’s not an additional layer of difficulty. You could blow open the doors with your Shrapnel Grenades, but this saves only a little time, and it loses you an objective and your cover of stealth.
Sneak into the fort and kill the guards that get in your way. You have to move at high speed to meet your time limit, so fast kills are easier to work with instead of silence. After clearing each spot, look for the locked wooden doors that are right by each pair of chests. Pick them open and steal the chests within. Don’t stop to loot the ammunition boxes or other items that are here. Focus!
You save time by avoiding the flag; that’s your final goal here at the fort. Cut that down after you’ve gotten all of the chests. This is a good idea because you can still get everything done even after the time limit expires. At that point, reinforcements arrive. Getting the chests is really tricky once the base gets filled by guards, but cutting down the flag is still relatively simple. The flag is high above one of the watchtowers, so you don’t have to fight the reinforcements once you’re already up there. That makes it very effective as a final goal in case you run out of time.
There isn’t much more to it than that. You have to ditch the fort to complete the mission. Run right out the front door and sprint into the alleys of the city. Plenty of British troops follow you, so zigzag through the alleys so they can’t get a good line of sight on you. Use pulleys to reach the rooftops if you see any of them available. Either way, the guards fall behind and quickly give up the chase. You’ve won and gotten both optional objectives without missing a beat!
Fast travel north, to Greenwich. The next stage is up there.