The Twin-bladed Knife is being held inside Doloros Michaels' Bank. You've researched the security system and planned a heist accordingly. Travel to Upper Cyria, break into the bank and steal the knife within.
Billie awakes on the Dreadful Wale and heads up on to the deck, Daud is sitting in an armchair by a table with all the information about the bank on it. Billie and Daud discuss the various methods of entry to the bank. Once Billie knows all she needs to, she can head out. The rail car is back at the station, but if she left the previous mission in the skiff, she can choose to take that to Upper Cyria instead, changing her arrival point from outside the station gates to the canal.
Once she arrives, Billie needs to make her way to the bank and get inside by one of the three entrances. She also has a choice of finding the laudanum to put everyone inside the bank to sleep.
The key to access the rubbish disposal is with Anibal Garca, the bank custodian. He lives in the small apartment just above Brozenar Taxidermy and relatively near to where Billie begins the mission, regardless of whether she took the skiff or the boat. Reading the note Meet Me at the Cliffs reveals that Anibal went to the sheer drop to the right of the bank entrance in an attempt to retrieve a valuable pocket watch he saw there.
When Billie arrives, a group of rats inform her that Anibal's dead body can be found partway down the drop. Reaching the body, Billie can retrieve the key. She must then make her way to the other side of the bank, to the whale oil tank refilling station. Opening the door there will let her access the disposal dumpster.
Billie must climb into the dumpster and shoot the control button to its right through the grate with any of her voltaic gun ammunition except for the hagpearl. The dumpster will automatically close and move to inside the disposal room, in which is a door to the main bank. It is possible for Billie to skip trying to find Anibal and simply go straight to the dumpster using Displace to bypass the locked door.
Under normal circumstances, there is no way to access the roof of the bank from outside. However, at this time there is a painter's lift to the unguarded right side of the bank's front door. While the lift is intended to help paint the building opposite, Billie can reach the roof of the bank using Displace or Agility once the lift is at the top of its path.
When Billie arrives, the lift is in its ground position but is almost out of whale oil, and so can only rise a short distance. The whale oil tanks are located to the right of the main entrance to the bank, where the rubbish disposal is, and that side is guarded with a wolfhound. Once a tank has been retrieved and inserted, the lift can rise up and Billie can reach the roof.
Once on the roof, there are two doors into the bank. The most obvious is next to the ventilation unit on the far side of the roof. Alternatively, there is a small room with fans in the ceiling just below the roof. One of these fans is open for repair, allowing Billie to slip through the gap presented and enter the bank via the door in there.
Shortly before the mission, Billie arranged for a street urchin to damage the walls to the tunnel underneath the bank's entrance. When she arrives, a worker will be there repairing the wall, and the access wrench will be in a box behind him. Billie must collect the wrench and use it to open the panels that control the two sewer gates. These panels are located to either side of the stairs up to the main entrance to the bank, making it effectively impossible to do without being seen. However, there is a guard standing near the stairs up from the tunnel, out of sight of the other guards and with his back turned. Both he and the worker in the tunnel are good candidates for Semblance and both have permission to be in the area. However, there are a few wolfhounds in the area, and Semblance does not trick them, so Billie must exercise with some caution.
Once the hatches have been opened and the crank wheels beneath them turned, Billie must return to where she picked up the wrench. Continuing on down the tunnel will lead to a hatch that is now open. Passing through will take her to the sewer system beneath the bank, from which she can access the bank itself. The sewers also contain a door, one that can only be opened from that side, that leads to the ledge on which Anibal can be found. This is also near the painter's lift, allowing Billie to collect the whale oil tank and move it to the lift with almost no chance of getting spotted.
Cienfuegos Pharmacy was known to keep laudanum, but was shut down by the bank when its owner, Eleuterio Cienfuegos, was killed. If Billie visits the store, she finds a petition on it, directing all those who wish to sign to Teresia Cienfuegos on Ferella Way. Talking to Cienfuegos will reveal that all the property of the pharmacy is being sold in an auction that night at Colibron Plaza, and that it includes enough laudanum for Billie's purposes.
As the auction is protected by the Grand Serkonan Guard, Billie must use Semblance upon a nearby aristocrat to gain entry. If Billie is careful, Semblance lasts long enough to enter, win with 500 coins, and leave the auction without being detected. Alternatively, the laudanum can be purchased from the nearby black market shop for 800 coins. The laudanum is inserted into the ventilation system on the roof of the building.
Accessing the Inner Atrium
Once inside the bank, Billie must find and recover the Twin-bladed Knife. To do this, she needs to access the Inner Atrium. If Billie entered via the sanitation entrance, she will already be inside the Inner Atrium. If not, she must access the control panel behind the teller desks to open the doors.
If Billie entered via the basement door, she will already be behind the teller desks and can reach the panel. If she entered from the roof entrance next to the ventilation shaft, she will be outside, and must go to the fourth teller desk and use her voltaic gun to shoot either the button marked "TELLER OFFICE" to open the door to the right of the teller desks and let her access them, or the big red button that opens all doors. Alternatively, there is an open window on the second floor that leads to the teller desks. If she used the roof entrance in the room with the fans on top, she will be by a staircase, from which she can access the main area or the teller desks.
Once past the doors, Billie's next obstacle comes in the form of two arc pylons. Each is located on rails. If Billie can access the rooms behind these rails, most easily by using a combination of Displace and Foresight, she can pull the lever moving the arc pylons into their storage location, also deactivating them, or rewire / depower the arc pylons.
After passing through the doors at the far end of the entrance, Billie is in the Inner Atrium itself. There, she has two objectives: find out how to move the vault and find Dolores Michaels and her key. The lift to access the rest of the Inner Atrium is protected by a wall of light, but the whale oil tank powering it is close by. There is a Clockwork Sentinel patrolling nearby, but it can easily be avoided, especially if it has been marked using Foresight. Also, unlike Clockwork Soldiers, Clockwork Sentinels cannot see behind them, only in front. Once the Clockwork Sentinel notices the deactivated wall of light, it will become alerted and begin searching the area. However, if Billie times it correctly, she can open a door bolted from the wall of light side and put the tank back in, powering up the wall of light again by the time the Clockwork Sentinel next sees it. This way, Billie can go back through the door to the area behind the wall of light without alerting anyone. Alternatively, Billie can rewrite the wall of light, and it will not fry the sleeping guard nearby either.
Opening the Vault
Climbing the stairs to the third floor will take her to Michaels's office. Underneath her desk is a button that controls a secret panel built into the painting on the wall. Behind the painting is Michaels's vault key, needed to access the vault. The office is protected by an inactive Clockwork Sentinel, and Michaels herself and Meryl Jennett are in the office at the time.
Located on the second floor are the security and administration offices. The door in is locked, and will not open without the code, which is found on the belt of Security Chief Alexander Peña, who is down in the basement checking on the lockboxes. Taking the note Important - Do Not Forget from his belt will reveal the current code to the security office, B15D. The guard will open the office door once given this code over the microphone by the door.
Once inside, Billie must make her way past the electrified floor to the vault control room. From there, she has the choice of moving the vault to one of two places: the director's office or the archives. Once the vault begins moving, the guard in the security office will question the movement as he was not aware of it. Billie has three choices: tell the guard there is a robbery in progress, tell him the vault is being tested, or say nothing. If she chooses the first, the guard will summon the other guards to the vault control room, waking them up if they were asleep. If she does nothing, the guard will again become suspicious and send security to the vault, suspecting a robbery. If she tells him it was a mechanism test, he will become annoyed that he was not informed, but let it pass.
Robbing the Vault
Once Billie has reach the main entrance to the vault, she must use the vault key to open it and get inside. The fourth safe is locked by two keys instead of the three-digit combination used by the other safes. These two keys are Ivan Jacobi's Key and Shan Yun's Key, which Billie stole in the previous mission. Opening the safe will reveal the Twin-bladed Knife, which Billie goes to pick up before being dragged into Void.
There, the Outsider reveals to Billie that he knows her entire plan, and tells her that Daud died in the armchair on the Dreadful Wale where Billie left him. Afterwards, he returns Billie to the world. From this point on, Billie uses the Twin-bladed Knife instead of her previous assassin's blade as it provides her with two new supernatural abilities: Bonecharm Crafting and Void Strike.
Leaving Upper Cyria
Billie must now make her way out of the bank and proceed to either the skiff or the rail car to return to the Dreadful Wale and finish the mission. If Billie left via the skiff last time and arrived via it this time, she will have to leave by the skiff as the rail car will not be there. If she left via the rail car last time and arrived that way this time, she will have the choice of using the skiff or the rail car to leave.
- Unlucky Target - Stole the contents of Dr. Galvani's safe.
- It's a Steal! - Robbed the Black Market in the Upper Cyria district.
- Repeat Offender - Robbed the Black Market in the Upper Cyria district, twice.
- A Pleasant Slumber - Sedated the bank personnel using the poppy tincture.
- An Eye for Art - Stole the painting from the delivery boat.
- Pickpocket's Delight - Took the note from the Elite Guard without him noticing.
- Bragging Rights - Retrieved the gemstone from Dolores Michaels' bank.
- Stolen Information - Copied the address from Mrs. Jennett's address book without being detected.
- The contracts in this mission are Rags to Riches to Rags, Quiet as a Mouse, The Art Connoisseur, and Pickpocket's Delight.
- On the briefing table at the beginning is a map of the bank. However, Billie cannot add that map to her journal.
- If Shan Yun was murdered in the previous mission a small memorial will be set outside of his Manor's front door.
- It is possible that certain of Billie's actions during Follow the Ink, may lead Ivan Jacobi and Eolina Rey to commit suicide, their bodies found at their respective homes.
- One of the lockers belongs to a "Morgan Yu". This is possibly an Easter egg to Prey, another game made by Arkane.
- If Semblance is used on Teresia Cienfuegos to attend the auction, upon winning the auction the auctioneer will talk to the Billie as if she was Teresia.
- On the bank's rooftop there is small bonfire with sword in the middle of it, which is an Easter Egg to Dark Souls series.
- Other five safes in a bank's vault belong to creator of the elevator vault, Kirin Jindosh. Code to unlock them is a Fibonacci numerical series. One of the most improtant things inside is a master override code to Clockwork Soldiers, which Jindosh built into them to prevent their use against him.