Assassin's Creed 2 Walkthrough

You've got to get the golden mask back from the bad dude who stole it. His location is marked on the map, but only with a large, vague green area. Move into the green area and climb a building so that you can use eagle vision to scout the area. He's located at the intersection of two major roads, and once you spot him he'll start wandering off.

Drop back down to street level, hire a group of courtesans, and start following the dude. If you lock onto him, you can use the courtesans to distract the target, causing him to stop in his tracks. Walk up behind the target and pick-pocket him to steal back your mask. With the mask in hand, you can now make your way toward the fancy party.

Ezio equips the mask as you near the party and a man in front of the party entrance will step aside to let you in. The sister greets you as you enter and suggests you use her courtesans to help stay incognito. After waiting around for a bit, a cut scene shows the big bad thief walk into the party and charge his guards with finding you.

The guards will slowly patrol the party, and if you get spotted the mission instantly ends. Do your best to blend. Find a group of partiers and stand in the middle of them, but don't expect the cover to last forever. As the guards move through, they bust up the groups and threaten to expose you. So as you wait in a crowd, be sure you look for an alternative hiding spot. Look around for a group of courtesans and lock onto them, ready to hire 'em and blend with them at a moment's notice.

Keep moving between blending spots until the timer runs down, at which point a cut scene shows the arrival of the Doge. The Doge stays on a boat just off the water. Hire a fresh group of courtesans and meander toward the boat, waiting at the short fence. The sister gives you the suggestion to use your pistol to take out the Doge from afar—sounds good to us!

Blast the Doge and then make a hasty retreat from the area. You need to become anonymous to complete the mission, so just jump into a river and swim under a bridge.