- (Optional) Speak to Vex about Vald.
- (Optional) Speak to Maven Black-Briar about Vald’s debt.
- Go to Riftweald Manor (Mercer’s house in Riften). You will need to pick several locks to reach his backyard.
- You may be confronted by his servant, Vald. Bribe (possible only if you’ve spoken to Maven) or kill him.
- Shoot the contraption underneath the top balcony with an arrow and a ramp will fall down.
- Head up the ramp and enter Mercer’s house.
- Kill any bandits you find inside or sneak past them.
- Head downstairs. You will find a wardrobe with a false back that opens to reveal a secret passage.
- Follow the underground passage through until you find Mercer’s secret office.
- There, take Mercer’s plans off his desk. Also, pick the lock to the display case and take the sword, ‘Chillrend’. (This sword makes it easier to kill Mercer later in ‘Blindsighted’: if you hit Mercer with Chillrend, he becomes paralyzed and falls over, making it far easier to kill him.)
- You will find a hole that you can jump down through to the Ratsway, close to the Ragged Flagon.
- Return to the Ragged Flagon and talk to Brynjolf.
Head to the Ragged Flagon through The Ratway. Meet Karliah after entering through the door to the Ragged Flaggon and follow her as she leads you to the Ragged Flagon-Cistern where Brynjolf is waiting to confront you both. Follow them as they head to the vault then talk to Brynjolf. Tell him everything and he’ll instruct you to break into Mercer’s home and look for clues. You have a couple options here. Either fight Vald, sneak past him, or the nonviolent optional way to deal with Vald: Paying the Debt. If you want a nonviolent way to deal with Vald but don’t want to pay the debt, you can sneak to the back of the house and shoot the ramp contraption, Vald will become hostile and chase after you. Lead him to a guard and they will kill Vald. Loot his body and take the key.
First, talk to Vex in the Ragged Flaggon and learn about Vald’s debt to Maven Black-Briar. Then head up to the city and locate her. Check at The Bee and Barb first. She’ll agree to forgive his debt if you locate the Quill of Gemination at the bottom of Lake Honrichoutside of Riften.
From the Riften Stables, head south west till you get to the edge of the lake. Ahead, you should see a large ship docked at Riften. Swim towards the west most end of that ship and look west across the lake to Goldenglow Estate to a similar ship docked there. Halfway to the other boat the prow of Vald’s sunk row boat can be found at the bottom of the lake. For reference, a small island on the north will mark the halfway point. You’ll see half a boat prow sticking out of the ground and the quill is located in a strongbox with an level-dependant lock. Pick it, take the Quill and a leveled amount of gold, then head back to find Maven. She’ll hand you a note: Vald’s Debt to take to Vald atRiftweald Manor.
Head to the back gate of Riftweald Manor and wait at the back gate until he comes to talk to you. He’ll give you a key to the house and open the back gate for you for releasing him from his debt.
Get a good vantage of the mechanism under the ramp and fire an arrow. The ramp will crash down and you can now head up to the second floor and into the house.
The first room is unguarded. The next, has a single guard who should be stuck facing the west wall so you can sneak past easily. The stairs down are on the north west. At the bottom, another guard will be patrolling.
When you reach the bottom of the stairs, immediately face east and there will be closed doors. Head through them. On the north east kitty corner to the bared front door, you’ll see a Suspicious Cabinet. Open it, then open the false back panel. Inside is a stairway down into the cellar and enter the tunnel system.
After avoiding the pressure plate by the metal gate you see when you first start out in the tunnels, make a left and head south which leads to a trap room of circles on the ground. Looking at the tiles, head south 2 squares, west 2 squares, north 2 squares, west 2 squares, then finally south 2 squares.
The hallway after the trap room has a pressure plate trap right around the corner which will launch a series of darts in front of the plate. After this trap, on the right is a chest which was on the other side of the metal gate at the beginning.
Following along the hallway further, you come to the hallway of timed pendulum blades and battering rams. Sprinting is always good here. Once at the other end, head down the ramp and stop at the closed door. There is a dart trap trigger on the left side of the door. On the other side of the door are Mercer’s plans, a note: Many Thanks, a copy of Red Kitchen Reader, Chillrend in a case, Amulet of Stendarr, and a few less important items. On the desk is a statue “Bust of the Gray Fox”, which can be sold to Delvin for 500 gold. Continue along the path till you reach the entrance to the Ratway Vaults.
Fall down the hole and you are a right turn away from the Ragged Flagon. Return to Brynjolf and hand over the plans. Quest completed, now on to the next quest: Trinity Restored.