Honkai Star Rail: Who Is The Thief [Treasure Questline]

This guide showcases the location of the four suspects and the quest associated with it.

Honkai Star Rail features tones of companion missions that are considered side quests for characters that have been acquired. One such quest is for Hook, who will be featured in the Old Foreman’s Treasure questline, during which players are also required to find out Honkai Star Rail Who Is The Thief. 

Important: Trailblazers need to be level 16 to gain access to the Old Foreman’s Treasure questline.
Key Takeaways
  • Start quest with Julian in the Great Mine.
  • Find Hook near a Vagrant Camp using the space anchor at the Overlook.
  • Get a health checkup for Fersman at Natasha’s Clinic.
  • Inquire about Fersman’s missing vein detector after the checkup.
  • Talk to Hook outside the clinic to begin the quest.
  • Helper is nervous but innocent.
  • Merchant is not the thief.
  • Sampo reveals Cook as the thief.

Starting Old Foreman’s Treasure Quest 

First, to find out who the Thief even is, the quest needs to be triggered, which can be triggered by going to the missions tab, and the first objective is to head to the Underworld and interact with Julian there. Trailblazers need to be Trailblazer level 16 to gain access to it. 

Map Location
Map Location (Image Credits Exputer)
  1. Take the teleport on the bottom left, and then just head down. Julian will be standing next to Alina. 
  2. After exhausting the dialogue with him, you will be told to head to the Great Mine to search for Hook. 
  3. From where Julian And Alina are standing, open the map, and navigate towards the Great Mine.
  4. If you have the teleport at the purple marker already unlocked, then great, but chances are that you won’t.
  5. Therefore the waypoint at the Overlook can be taken as well.
  6. From the teleport point, pan right and start heading uphill, ignoring the robot that tries to ambush you, and instead keep heading deeper into the mine.
  7. Keep going until you come across a small area with a few tents set up and Hook standing at the very back with Fersman and two guards.
Talking To Julian
Talking To Julian (Image Credits Exputer)
Overlook Map Location
Overlook Map Location (Image Credits Exputer)

Talking To Hook 

Natasha's Clinic
Natasha’s Clinic (Image Credits Exputer)

After the cutscene triggers, Fersman can be seen being blamed and bullied by two Vagrants, and Hook attempts to stand up for him. If you try to intervene in the conversation, the Vagrants get angry, and a battle gets triggered. 

The battle for the starting of the questline isn’t all that tough since it’s just those two measly men who starter characters can trounce. 

Hook Being Worried
Hook Being Worried (Image Credits Exputer)

After the battle ends, Hook seems extremely worried about Fersman, since he takes quite the beating, and the MC and Hook both have to attempt to convince home to head to Natasha’s clinic to get a checkup for his health; otherwise, it could be adverse. 

Fersman Being Cornered
Fersman Being Cornered (Image Credits Exputer)
  1. From here, open the map, search for the space anchor right above Natasha’s Clinic, which is located towards the bottom left of the Great Mine, and teleports there. 
  2. From the space anchor, head inside a building where the quest is pointing. 

Asking Natasha About Fersman’s Condition

After you make it to her clinic, Fersman can be seen sitting on a chair while Natasha attempts to check on his wounds. 

Natasha Inquiring About Fersman
Natasha Inquiring About Fersman (Image Credits Exputer)

Interact with Natasha, and she will mildly bicker with Hook about the fact that she was the one who caused the trouble and that she was the one who ended up making Fersman deal with the 2 Vagrants that were fought before. 

Giving An Ultimatum
Giving An Ultimatum (Image Credits Exputer)

Inquiring From Fersman 

After Fersman starts feeling better, you can see the plotline about Thief being developed. 

Inquiring About Fersman
Inquiring About Fersman (Image Credits Exputer)
Selling It To Antonia
Selling It To Antonia (Image Credits Exputer)
Losing The Detector
Losing The Detector (Image Credits Exputer)
  • As Stelle (the female MC) looks over at Hook, it seems Hook wants to talk to us outside the clinic. 

Interacting With Hook 

After that interaction, you need to head outside the clinic, leave Fersman alone and instead talk to Hook. 

Map Location
Map Location (Image Credits Exputer)

Hook will be waiting outside the clinic’s main entrance and standing a few feet from a street lamp. After interacting with her, you find out that she is on a mission to get back the vein detector, and she will do anything it takes to get it back for her father. 

Hook On Her Mission
Hook On Her Mission (Image Credits Exputer)
  1. After that, you can take the Space Anchor, which is located at the Vagrant Shelter, where you need to head to the Great Mine and meet up with Hook once again. 
  2. While interacting with her, she introduces us to Swetta, and she confirms that the vein detector was indeed stolen.  
Swetta (Image Credits Expu

She goes on to say that when she returned to the mine, the detector was gone, and even after searching all around the shelter, it was nowhere to be found. However, Swetta was about to narrow down a total of 4 people who might be the key to the Who Is The Thief quest.

Investigating The Four Suspects 

From here, the four suspects will be scattered around the vagrant shelter, and you are to investigate them all. 

Cook Standing
Cook Standing (Image Credits Exputer)
  • The first suspect is standing towards the right side of the Vagrant Shelter, and he will be standing between two tents behind a small campfire. 
  • The suspect’s name is Cook, and as he greets you, Hook instantly skips to the point and asks him to spill whether he stole her father’s detector. 
  • Cook calls Hook a brat and asks her how she dared to label him as a thief, and that someone needs to give her a few lessons on good manners, and that he is a sincere and decent man and that he would never do such a shady thing. 
Cook Being Mad
Cook Being Mad (Image Credits Exputer)
  • After that, you can start to investigate Cook by asking him questions like what he did when the crime occurred if he knows and his opinions of Mr Fersman. 
  • Upon asking the first question, he says he’s a cook and was shopping for ingredients at the time of the crime (nice rhyme). 
Helper Over There
Helper Over There (Image Credits Exputer)
  • When asked if he saw the detector, he tries to derail the situation by saying that the “helper over there” might be the clue to finding the Thief since Cook saw him enter Fersman’s tent and came out with a box in his hands. 

Second Suspect 

As far as the second suspect is concerned, you can go over to Tailor, who is standing a few feet away from Cook. 

Suspect 2
Suspect 2 (Image Credits Exputer)
  • While Tailor seems to be the most suspicious here with her mannerisms, when asked about what she was doing during the crime scene, she ends up being honest and says that she was spacing out and didn’t happen to notice anything. 
  • Hook confirms the suspicions and agrees that she isn’t the thief. 

Third Suspect 

The third suspect is standing towards the right of Tailor beside the Space Anchor. He is a helper, and he can be interrogated as well. 

Suspect 3
Suspect 3 (Image Credits Exputer)
  • Helper seems way too nervous to be lying and saving himself if he did commit the crime, as when he is asked about his actions during the crime scene, he says that he went out for fresh air and then immediately becomes nervous and says that it’s a lame alibi but at least it’s true. 

Suspect Four 

Last but not least, the fourth suspect is standing a few feet away from Helper, and Hook instantly starts interrogating him with the needed questions. 

  • The merchant becomes angry at the thought of being accused, and there is an option to rule him as suspicious in the first dialogue option. 
Suspect 4
Suspect 4 (Image Credits Exputer)
  • At first, he keeps his mouth shut and doesn’t answer any questions, but then he asks if a deal can be made, and he’ll honestly tell you what he knows. 
  • After he’s asked if he has seen the detector, he comes clean and says that Cook is the thief and that he wouldn’t lie since he values his reputation more than anything. 

Choosing The Thief 

From here, Hook leads us back to the camp, and there are a total of 4 options that you can sift through. 

Choosing The Thief
Choosing The Thief (Image Credits Exputer)
  • The answer to the Who Is The Thief can be the cook, the helper, the merchant or the tailor, or help can be taken from Hook herself. 
Collecting Clues
Collecting Clues (Image Credits Exputer)
  • If a wrong option is chosen, such as the Helper, Hook interrogates the suspect again and concludes that they are not the thief and that another round of interrogation should be done. 
  • After that, you will need to run around to collect items like packaging labels and other clues that would lead you to the culprit. 


And that’s about it! All that players need to know about Honkai Star Rail Who Is The Thief, and with that, let’s wrap it up! While you’re here, why not read up on the Honkai Star Rail Bronya Build, which goes into detail about the best light cones, best relics, and the overall playstyle for Bronya herself? Alongside that, the Honkai Star Rail Treasure Map guide will entail details about all the potential locations for the treasure map!

With that, the Honkai Star Rail Road To Revival Mission guide details the mission and its walkthrough! Lastly, the Tingyun Build Honkai Star Rail guide will discuss her light cones, relic options, and her best team comps!

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Mina is a Senior Guides Writer and a fanatic who’s obsessed with playing games and writing about them. She’s invested more than 2,500 hours in games like Genshin Impact and Honkai Star Rail. With a Bachelor’s Degree in Journalism, she loves to write detailed guides for beginners and pros in the Gacha Games world. You can follow Mina's gaming activity on her Steam and PSN Profiles.

Experience: 3+ Years

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