In the last chapter you discovered a hidden tunnel leading from the hideout, and followed it, fighting with some guards along the way, until reaching a dark, narrow cavern. Reach a chamber, locate the elevator door. It's stuck There's a counterweight above but looks like it stuck so the elevator wont move.Climb the ladder and then the pipes, then release the counterweight.
Go through the opening, stand on the metal beam. Some more of Marlowe's guards will come. Aim and shoot the closes one from above.
Hop on to the wall and move along it. There are two more guards on the floor. You spot Marlowe's car. From here on, no more guns.
Jump from one Chandelier to another to reach the other side of the chamber. Climb down the wall.
Take down the next enemies using stealth. To perform a stealth attack, approach an enemy unnoticed, then press the square button. Explore the big room.
As you approach the hole in the wall at the end of the room, you will hear 2 more patrol coming. Take cover behind the wall. Take them out, quietly. To stealth attack from cover, press square when the target is near. Go through the next tunnel.
Go up the stairs and past several display cases. There will be a cutscene. You finally found Marlowe and her gang. Close in quietly to overhear the conversation she is having with her people.
Kate takes out the decoder and tries to insert the ring into it. It does not fit, since the ring is fake. She realizes it is a forgery and is not happy. She realizes they were duped and could have been followed and tells her men to be alert.
Drop on the guy beneath you. Press left stick forward and X button to vault over cover. Press square when on a ledge over an enemy to drop onto him and knock him out. To move along an edge in cover, use left stick. Then press Square to stealth attack.
There will be another cutscene. Inspect the book that belonged to Lawrence of Arabia. Place the ring on the cipher disk. It will start turning. The code is L O H D N Long Hidden. Its an anagram for Golden Hind (Drake's Ship). It has to be something hidden in this room. Spread out and see what you can find.
Take out your journal and press select to read it for clues. See the golden hind head circled in red.
Look for it in the room. The figurehead from Drake's Ship is up high on a pillar, above one of the paintings. Climb on the fireplace, then go left and climb over a painting, Jump across to the pipes, go around the pillar and jump to where the figure head is, press green triangle. Two guards will enter. Shoot them from above.
The figurehead will break and a map will fall from it. Grab the journal and the cipher disk. Neutralize remaining guard and grab his weapon. Retrace through the tunnel. When you reach the train station room room there will be a big battle with lots of guards. They will be armed with goggles and machine guns. Kill one of them and grab his KAL 7 gun to be able to use auto fire. Use the KAL 7 to get rid of the other guards. Press Square to avoid laser targeting.
More and more guards will enter, neutralize them all. Remember to grab weapons and ammo from them. Work your way through the station and climb up the stairs. Other available weapons in this room will include a M9, Mag 5, and a Sawed of Shotgun.
Climb the ladder and then through some more stairs. Follow the rail tracks. You will come across yet more of Marlowe's goons. Make sure to avoid their laser targeting by hitting square. Shoot them from cover behind the crates. They will use smoke bombs making it harder to aim at them. You will be in the North Atwood Station. Keep moving. Take cover and kill the next guards that come in. Use the train and the dumpsters as your cover. Radio to chloe that you are coming up the north Atwood station and you've got company. Climb the stairs leading out from the station. There will be yet more enemies upstairs so be ready to shoot them. Use the automatic rifle if you have the ammo. Keep going up the next set of stairs, neutralizing any enemy you run into along the way. Shoot the lock on the door and exit. Chloe will be waiting for you in the van. Enter the van and drive off. This will end the chapter.