Once a Thief is a Story Chapter in Uncharted 4. It is Chapter 6 in the campaign.
Once a Thief Video Walkthrough
Once a Thief Text Walkthrough
This chapter begins with a cutscene followed by a climbing sequence. Follow Sam up and then down, where you can find a treasure on the left. Head to ledge to spot the beam beneath the bridge. Toss the hook at the beam and swing across to the cliff wall. Drop to the lowest part and head left. Sam will grapple onto the beam and swing. Take the holds down the wall and head to the rope, grabbing it when in reach. Wall run and leap to the next ledge. Continue left to the branch and swing to the stone wall. Hang on the wall to let the guards pass before climbing up.
Pull up and follow Sam through the citrus trees. Head right to find a treasure and follow Sam to the corner to speak with him for a conversation. Head to the balcony to view your destination. Inside the hut, go down the stairs and grapple to the beam. Go over the balcony and hang, then rappel down the rope. Wall run to leap across to the lower ledge.
Walk through the pillars, watching for another conversation prompt from Sam. Climb up the arch and look left to see a pole protruding from the cliff. Jump to it and swing to the next arch. Walk left and along the ledge to the wall. Climb up and swing from pole to pole and onto the rock. Sam will follow and climb up and grapple the light fixture. Grab the rope to trigger a cutscene.
Turn around before following Sully and enter the room behind to find a treasure. Leave the room and speak to Sam on the balcony for a conversation. There is another treasure on the balcony here. Head back in and follow them to the main floor. There is an acution sheet on the table near the bottom of the stairs. Go across the room to the cellar which is locked. Use the mini-game to pickpocket the waiter for the key. After 3 misses, Sam will distract him to complete the task.
Go back to the cellar and open it to trigger a cutscene. After, head left into a room to find a treasure. Then follow Sam into a hallway and downstairs. Look through the window to see the gunmen and head downstairs to find a locked gate. There is a treasure just underneath these stairs.
Head to the large wine barrel on a cart and push it aside to open the door. Find another barrel with a red ring and pull it out. Head into the opened passage and pull another barrel out. Head through the openings and pull a cask here to the vent. Climb it and enter the vent. Follow the duct out to a grate that won't open. Turn around and follow Sam to a loose grate and follow Sam. After letting some guards pass you can exit to a courtyard.
If you take the firescape around a corner here you can find a treasure. Follow Sam to the gate and press triangle. Head to the wall with the raised ladder, and work with Sam to boost him up and kick the ladder down. Climb to the next balcony, where you can find another treasure on a balcony near here. Follow Sam into the courtyard and boost up to the other raised ladder here. Sam will take the waiter's uniform here.
Go across the courtard and climb up. Head right and go down the stairs and climb to the arch's roof. Find the door to the power room. Jump to the gazebo roof in the center of the courtyard and then jump to the next roof. Go up the wall to the roof. Jump to the poles to trigger a cutscene. The pipe will break and he will slide down.
A cutscene will play in the gala. Back to Nate, head to the pole and jump to grab it. Let go and drop down to a pole. Nearby is a treasure. Climb up the wall to another pole and swing to another. From here swing to a longer pole and face the opposite way and slide right. Climb on the wall around the corner and to the top of the pipe. Go left on the pipe around the corner and continue to climb up the the open window at the top left.
Go to the end and drop down. Press triangle at the gate which is locked to trigger a cutscene. Search the marks in the room to find a crowbar. Open the door and and interact with the circuit box to trigger another cutscene and the chapter's end.
Once a Thief Collectibles Locations
|Mughal Water Container||Treasure #7||On the top of the cliff, at the cliff's edge (opposite the wooden bridge you rope on to).|
|Nephrite Brass Cup||Treasure #8||Building window, near the citrus trees. Straight ahead from where you climb up into this area.|
|Conversation 3||Conversation||In the area with the trees, walking around will trigger it.|
|Conversation 4||Conversation||Stay near Sam after swinging on the rope, watch for the prompt as Sam walks near you.|
|Viking Cloak Clasp||Treasure #9||At beginning of gala scene, turn around and enter the room behind. Treasure is on a shelf.|
|Mother of Pearl Horn||Treasure #10||Balcony on top floor of the gala, on the right side.|
|Conversation 5||Conversation||Speak to Sam on the balcony.|
|Persian Bronze Bowl||Treasure #11||In the pantry, after stealing the key from the waiter. In the corner, behind a crate to the left of where you enter.|
|Brass Barber's Bowl||Treasure #12||After exiting the pantry, at the bottom of the stairs. It's in the wine cellar, just after you get the prompt to peak in at the guards.|
|Syrian Vase||Treasure #13||Exit the air vents to the garden. Drop down to the railing on the left and into the lower section. Use the ladder to reach the rooftops, treasure is on the first lower roof.|
|Persian Candlestick||Treasure #14||After Sam drops a ladder for you on the roof, ascend it and climb the structure on the left. Jump to a balcony on its left. Treasure is on the balcony.|
|Mughal Dagger||Treasure #15||After dropping into the dark, muddy area post cutscene. Swing across the pole ahead. Hang from the cliff to your left and climb in the direction from where you came. Treasure will be found on a ledge.|