The Combination to the Great Safe
Remain Undetected - 350 G
Pick 8 Pockets - 275 G
10 Kills or Knockouts - 250 G
Lift All Loot Items - 280 G
At the start of the chapter, head over to the Shady Merchant and stock up on arrows and rope arrows - and also make sure you buy the Razor Tool and Wrench Tool. If you need focus points, you can buy those from the Queen of Beggars.
Objective 1: Find Jacob in Greystone Plaza
He's pretty much right in the middle of the plaza, so just walk into it.
Objective 2: Head to the Architect's Grand House
Follow the objective, and pick up any loot that might be along the way. There are a few tricky ledges, so be careful. After the cut scene showing an explosion at The Keep, slide on down the rope and grab the poppy. Now fire a Rope Arrow in the anchor beam above. Climb down toward the two benches and you'll find the Serendi Stone Circles (4/7) - Lapis Lazuli Circle. You should have four at this point, so if you're missing one or more, check the previous three chapters for their locations. Don't forget to pick up the arrows from the box on the barrel. Climb back up the rope and continue forth.
Objective 3: Make your way Inside the House
If you're particularly stealthy, you can sneak past the five guards without being detected. However, it's easier to take down three with headshots, and eliminating the other two by shooting a Fire Arrow into the ground next to the northeast barrel. This makes a lot of noise, so make sure you do this last, otherwise you'll have the other three guards to contend with. The best trick it to use your Focus to look at the barrel and wait for the guards to pass by and then shoot. Once the guards are taken care of, you can then deal with the dogs. No worries about making any noise at this point - nobody is alive to hear it.
Check out the outside grounds of the mansion and head over to the sheds to the east and west. If you use your focus and look north east, you'll see a ladder. If you shoot the gear next to it using a blunt arrow, you can gain access to a small entrance that leads you to mansion’s top floor. However, don't go in yet, as there's something you need to do.
Climb the ladder, but rather than go for the entrance, move west along the balcony and take out the guard. Leap over to the top of the greenhouse and drop through its roof. There you'll find a bag of food and a poppy. At this point, it's a good idea to save the game. Look for a loose brick and hit it to open a secret passage. Climb down the ladder and look for a control box, which you can use to disarm a trap. Sneak down the passage until you reach two peepholes. Watch the cook, and when he leaves the room, check the south peephole and press the button on the wall.
Objective 4: How to get up to the Architect's Study
Hack the control box, and then wait in the northwest corner for the cook to return - and then sneak up behind him and knock him out.
Note that the control box is optional. If you only care about getting the Remain Undetected Thieving Challenge, go back from whence you came, and use the lift to go directly to the architect's study. While this is a nice shortcut, you'll miss out on a fair chunk of loot.
Stealthily head up to the kitchen. There's a guard here, so you'll have to be quick. As he tries to leave the room, hit him with your Blackjack and take him down. If he does leave the room, sometimes he stands in the foyer - if he does, aim at his head with a Broadhead Arrow, and that should take care of things.
Now you can explore the first floor. Grab all the loot you find, but make sure you save the east room for last. Inside the room, there's a button on the side of the desk which you can press to reveal a safe on the north wall. Pick the lock and hey presto! Unique Loot (4/9) - Morendrum Medal is all yours. When you have all the loot the first floor has to offer, save your game and head upstairs.
Upstairs are two rooms, each with people inside. There's also a lone guard at the top of the third floor stairs, trying to get into the study. Once you're on the second floor, go into the southeast bathroom. Now you can sneak into the northeast room and knock out the maid and the architect's wife. Once that's done, go to the northwest hallway where you'll find another guard and maid. Take out a caged bird with a Choke Arrow, sneak into the room and climb up onto the bookshelves. Take down the pair of people however you want, but do it quickly because you won't stay unnoticed for long.
When they're down, go back into the hall and up the stairs toward the guard by the study. Knock him out, use the Razor Tool and snag The Court of Montonessi (8/12) - The Abundance of Emptiness. If you are wondering where the previous seven are, they can found in various parts of The City and by doing a few of the Client Jobs. Go back to the room where you knocked out the two women and loot it, making sure not to miss the safe. There are quite a lot of valuables in here.
Return to the room where you took down the guard and maid and look for a specific book that you can pull off the shelf. Use your Focus if you need to. Once you've found the book and grabbed it, a secret passage is revealed. Go inside, press a button on the wall and ride the elevator. When you reach the top, go into the passage and press the button to gain access to the study.
Objective 5: Search the Study for the Keep Plans
Ascend the ladder to the balcony and then check the painting on the wall and feel for the triggers. Once activated, a model of the Keep rises majestically from the floor. Go check it out, and then arrange the pieces to match the Keep that you can see just outside the window. Solve this puzzle to complete this objective.
Objective 6: Steal the Plans and Escape
On the bookshelf you'll find the Keep Plans and Great Safe Combination. Grab those, and run north to escape. Don't stop for anything.
Objective 7: Get to the Keep
Watch the cut scene, and then turn left and visit the Shady Merchant. As usual, stock up on everything. Don't be stingy.
Now head east and climb a rope which leads to an attic. Crawl through the passage and make your way toward the Keep.
Objective 8: How to get Inside the Keep
Since everyone here's dead or dying, don't bother to sneak. The only thing you need to worry about is the Keep itself. Head towards the objective, and don't get hit by one of the exploding pipes. Drop down to the walkway, and then jump to the large pipe. Move east along it to the large piston. Time your passage through it correctly to avoid being squished - go when it retracts. Head through the passage to complete your objective.
Objective 9: How to find and Rescue Basso
Don't stand in the fire. It hurts. Head to the southwest corner of the room and turn a valve. Go north and then turn west and you'll find a control box and door. Work your magic on the control box and you know what happens. Go inside the newly-opened room and grab whatever's inside. The smoke in this room harms you, so keep an eye on your health and eat some food if need be. When you are out of the smoke, pick the locked door to the east.
Look ahead and you'll see the body of a dead guard. Search it to find Memories of the Dead (3/6) - Soldier's Memory. Now continue to the far east where you'll find the City Heritage Plaques (12/16) - The Keep. Many of the City Heritage Plaques are not found within the chapters, but in The City itself.
Get on the elevator and take a ride upwards. When you reach its destination, scour the area for loot, and once you've cleared it out head toward your objective. When you reach a lever, pull it and move through to save Basso.
Objective 10: Find the Great Safe
Time to ride the elevator to the roof, which you can reach be climbing through a hatch. Move through the passageway and jump down to the floor below. Approach and pull the lever in the middle of the room to reveal the safe.
Objective 11: Open the Great Safe
There are switches on each side of the safe which need to be pressed quickly. Just go from one to the fast until you trip them. When the locks are reset, go to the dials to enter the combination. Each of the pair of dials has its own combination. Left is There are two sets of dials: right is 0, 1, 8 and left is 3, 1, 9.
When the cut scene ends clamber up the wall that's east of you. Now sneak over to the crate and hide behind it. When the guard on the landing isn't looking, take him down. Now hit the control panel's button to turn off the lights. Head back to the alcove where the guard was patrolling, and you'll find The Moral Coils (4/6) - Shale Snake Bracelet. If the loot number doesn't match the one in this guide, you've probably missed something along the way, so check what you have vs what this guide lists. It's a good inventory check at this point, since there's nothing left to collect in this part of the game.
Return to the control panel where you knocked out the guard, and use broadheads to take down the search party from a distance.
Objective 12: Steal the Primal Stone
Once all the enemies are taken care of, head back to the safe and enter the right combination again. The safe opens up and you can grab the Primal Stone contained therein.
You can find many more hints and tips, plus strategy guides and over 65,000 cheat codes, unlocks, achievements, trophies, Easter eggs and secrets at Prima Games.