Nate and Flynn began following their path through the sewers, looking for a way into the museum. After climbing just a few pipes and ledges, the two came to a dead end, but Nate spotted above him a brick-lined shaft that would take them up into the boiler room. Flynn gave Nate a boost up, and the latter led the way inside. From there they managed to make their way to the inner courtyards, and a clear view of their target location: the tower that held the oil lamp. However, they could only get there from the roof, and to get to the roof, they would need to make their way to the next courtyard, through a gate across from their current position. The two proceeded towards the location, knocking out museum guards and climbing several structures.
Tipping the Odds
As they pressed forward, Nate and Flynn climbed inside through a window, and they entered a room full of guards. Flynn decided it was time they tipped the odds back in their favor, pulling out a couple of guns, which Nate believed was a bad idea until Flynn told him they were tranquilizers. On the other hand, Flynn pointed out that due to the poor range of the guns, the two still would need to get in close for a shot. After taking the guards down one-by-one, the two made their way to the roof from where they spotted the tower again, realizing they were getting closer. Upon finally making their approach to the tower, Chloe shut off the lights, allowing them to enter.
Once the two dropped down into the Marco Polo exhibit, Nate began searching for the case that held the lamp. Upon finding it, Nate pointed out the acoustic alarm, which would go off if one was to even touch the glass. This was no issue, as Flynn had a key to unlock the case with and managed to open it without triggering the alarm. Nate then grabbed hold of the lamp, but to know for sure if they had the right lamp, Nate had no choice but to shatter it to pieces and see what it contained. They found nothing but a blank, brown piece of parchment paper, much to their disappointment. As Nate sorted through the chunks of resin that also came out of the lamp, he examined one of them closer and recognized it as the "light of the great Khan", knowing it would burn and reveal the hidden marks Marco Polo left on the paper.
Nate rounded up all the resin and used Flynn's lighter to light them. He then took the parchment paper and held it in the light, thereafter he was able to read what Marco Polo wrote. It revealed that a tsunami has struck Polo and his crew, leading to their shipwreck somewhere off the west coast of Borneo. Upon reading further, Nate was astonished to find that Marco found the lost city of Shambhala and acquired the Cintamani Stone. While Flynn took the paper, Nate figured that if Marco and his crew were carrying the stone, it could still be in Borneo.
Flynn then proceeded to leave without Nate, having climbed back up to the door and rounded up the rope he lowered, leaving Nate with no way up. Flynn then drew his gun on Nate, but instead of shooting him, he triggered the alarms by blasting the glass on two of the display cases. He also revealed that he had already known about Polo's fleet from the beginning. Flynn delayed Nate until the guards started closing in, after which he made his escape. Nate was then forced to make a run for it, eventually making his way back into the sewers. More guards followed him, but he managed to find an exit out to the streets, although he failed nonetheless as several policemen arrested him at gunpoint as he climbed out of the manhole.
After spending three months in a Turkish prison cell, Nate was simply trying to entertain himself by repeating Flynn's betrayal with his hands. Shortly after, Victor Sullivan approached Nate's cell, to Nate's excitement. Sully managed to pay for his bail after "greasing a few palms" and explained that Chloe asked for his help. Nate, however, was reluctant to trust Chloe's word, believing she had something to do with Flynn's betrayal. Chloe tried to assure him she had no knowledge of it. Sully then jumped in to mention that Flynn and his client, Zoran Lazarević, found the ships in Borneo but not the Cintamani Stone.
Knowing that they still had an opportunity to steal the treasure from them, Nate and his allies formed a plan to get into the dig site. After leaving the prison, the three got together elsewhere and looked up information on the Stone. Nate pointed out from an image in a book that described the stone as the wish-fulfilling jewel, a sacred object. He then recited some text to Sully, stating, "In the kingdom of Shambhala lies the most precious thing to be found in all the world, a perfect raw sapphire of the deepest blue, larger around the reach of a man's arms." The two then believed the Stone has got to be worth millions, or hundreds of millions.
Chloe mentioned that Lazarević paid top dollar for Marco Polo's journals and that he has been after the Stone for years. Nate believed that he could find the Stone, provided he could get a look at Zoran's files. However, Chloe warned him that he would find the files in Zoran's tent, in the middle of a heavily-armed compound, with soldiers patrolling everywhere. They then decided to use Chloe to create an explosion as a diversion for them to get inside Lazarević's dig site and steal the files.
Entering the museum
When you have control of Nate, get out of the water and head to the large, brick squares and pull yourself up. Simply follow Flynn as you go, jumping and climbing along as he does until you reach an apparent dead end, at which point the game prompts you to press . When Flynn gets into position, approach him and let him boost you up. Continue climbing until you reach the ladder that leads up to the boiler room.
Once inside, climb over the green pipe ahead, then go and stand beneath the ladder up ahead so that you can give Flynn a boost. Follow him up after he drops it down for you, then climb the ladder opposite of where he stops to find the valve that lets you close the steam vent. Drop back down and jump over the pipe, use the yellow bar to swing across to the platform, then turn to the left and jump towards Flynn. Press to drop down from the other side. Head to the left and press again to fall onto the yellow platform. Head towards Flynn and follow the on-screen instructions to take cover.
Crossing the courtyards
After the cutscene, head forward and go up the steps towards a large set of doors and press to trigger a brief scene. To disable the alarm, you will need to find the junction box. Head back down the nearby stairs, and at the second set of stairs, jump onto the crate next to the passage to find the junction box. Return to the doors and enter the new opening. Follow the on-screen instructions to subdue the museum guard, then go left.
After the short scene, drop down to the small garden below. Take cover beside Flynn, and follow the on-screen instructions again to sneak up on the guard. Next, head to the left and climb the portcullis, following Flynn to a balcony. You will encounter two conversing guards. Approach the guard on the right and follow the on-screen combat tips, while Flynn deals with the other one. Head forward, and after the brief scene, jump over the rail and head to the left as Flynn advises. The guards can all be taken out using any of the previous techniques, be it sneaking up on them by using cover, or simply rushing them while their back is turned to quickly knock them out.
Eventually, once all guards are unconscious approach the portcullis along with Flynn, where you will now need to disarm another alarm. Climb the portcullis, and then jump to the yellow ledges to your right to reach the box. After disarming the alarm, drop back to the ground and make your way to the second courtyard.
Upon entering the next area, follow Flynn's instructions and make your way to the fountain to the right. Vault over the rail, and hide behind the closest pillar. You do not need to knock out all guards, just those in your path; which leads across the right side of the yard. Head past the fountain, keeping it on your left, and make your way to a guard on a higher level, with his back to you. Climb up and quickly press pull him down. Two guards will appear ahead; climb over the rail and take one of them out, and Flynn will take care of the other. Head up the steps and to the right. When you press , Nate will point out a window far to the left. Climb onto the roof from here and follow Flynn and climb your way to the window. When you are hanging on top of it, drop down and climb inside, then fall into the next room where you trigger a cutscene.
Traversing the rooftops
After the cutscene, you will now be armed with a tranquilizer dart gun. Shoot the guard on the left, and Flynn will shoot the one on the right. Make sure you do not miss, or else you will be spotted. Pull yourself up over the ledge, and take cover behind the boxes to the far left. Shoot the guard on the second floor in front of you, and Flynn will shoot the other one again. Now you must look for a way up there. Look for the cart and press to get beside it. Press forward on to move it, with Flynn's assistance. Once it is in place, climb up the platform. Press and the game will direct you to some rafters above. Flynn will throw a grappling hook with a rope up against the wall. Ascend to the handholds above, and the second you grab onto them, a guard will open the doors below, spotting Flynn. Shoot him quickly to save your partner.
Continue moving across the ledges until you can start climbing the rafters proper, jump or shimmy across them to reach a walkway on the left-hand side. Exit out of this room through the open window atop the stairs. From here you have to follow Flynn across a series of rooftops again, performing a few jumps along the way. You will eventually reach another dead end and must use a second rope to reach a vent grating. Climb to the roof and take down the guard when prompted, then climb up top and head for the farthest unit that has a light attached to it. You will see a yellow ladder; grab hold of it, and once at the top, head to the right and move along the bars. When you are at the end, shoot the guard on the path below.
Follow this path and vault over the section of the ledge without the rails. Going forward, cross the rooftops until you reach the one near the tower entrance, where Flynn will meet you. Shoot the guard (or vault over the rail to melee him). Head to the tower to trigger a short scene where Chloe shuts down the lights on the tower. Follow Flynn to your entry point, when he opens the windows, walk up to him, and Nate will drop down into the exhibit.
After the cutscene, run into the opening across from you. Run down this path, avoiding the lasers by dodge rolling (). When you come around the corner, you will see an opening to your right, enter it and you will be going down a set of stairs. Once you reach a window, jump up to it, climb through, and then drop to the path that leads to a manhole on the far right. Once you are back in the sewers, keep running straight until you reach another room. In this room, keep moving forward and turn right at the opening ahead. Run towards the ladder at the end, climb up the platforms and then climb up to the manhole to exit the sewers.
Behind the scenes
The scattered newspapers on the ground list this level's designer, background artist, and QA tester as wanted felons.