Hey... we got some C-Four, that's waaaay better than a gun! Yep, sure is. Khan's handbag sure packs a punch! Enter the church and search the pile of stuff in the center of the room. In all, search it four times to find a pipe, coin, cog, and pen top, respectively.
Look at the demon statue to the east a few times. After that, look at the panel to the right of the statue. It doesn't move, surprisingly. Walk a little north of the statue and try to pull the lever. George, being a klutz, will break the handle. That's a good thing, though, because if you check the place where the lever was you'll get another cog and a spindle.
Put both cogs in the eyes of the demon statue. I guess that was why it didn't have any eyes. We still have one thing to put in the statue, however. Put the broken lever right in the demon's mouth. George will turn it and the door will open. Pretty cool how Nico figured that out...
Enter the new doorway and try to take one of the torches off the wall. Nico will correct you, however, talking about gunpowder. At any rate, go northeast and try to enter the new area. Nico and George will both here chanting and it's time for the game's biggest cutscene.
"Finally, the truth. The Templars had never worshipped this graven image, no more than they'd worship a rainbow. But, like a rainbow they regarded it as a symbol of a covenant with God, who'd revealed this place to them."
OMGWTFBBQROSSO! Grand Master (err... it's hard to refer to him as that) will try to recruit George but he's just too smart now. His biggest motivation to turn down the Grand Master, though, is probably Nico. They will start to run and meet up with their best friend.
Yes, that's right, it's Guido. When you first get the chance, throw the torch in the gunpowder. However, the stuff is over three hundred years old, so you got to wonder if it's going to make a bang or not. It doesn't, but Nico remembers what she has in her handbag. That's right, the person you stalked and thought was your enemy (and who is now dead) pulls through as Nico throws the explosives in the fire.
Amazingly, they don't go off right away. Even more amazingly, all the other bad guys don't run outside. The thing goes bang when the twosome are a safe distance away and then it's credits time. Thanks for playing!