This quest can only be started after completing the Fontaine Research Institute Chronicles quest series. During the quest, you will unlock an underwater ruin near the Tower of Ipsissimus to find the traitor hiding inside it.
An Expected Plan
➥ Teleport to Lumidouce Harbor and you should notice the quest icon on the map. Talk to the lady NPC to start the quest.
➥ The whole quest is relatively easy and you should be able to complete it by just following the quest navigation. For the first task, stay behind a huge container and listen to what those suspicious people are talking about.
➥ Once you defeat the attacker, keep following the navigation to meet another suspicious individual. Covault the drunkard is lying on the grass on the left side of the tavern. You will enter another small combat but it’s really easy. From there, just follow Covault.
➥ For the brainstorming game, the following are the answers:
- Interpret everything as far as it allows you to
- Associate [The transported Nacker] and [Loillier’s boss] (Writer’s Note: As you can see, my screenshot is blocking the top left option so if it’s wrong, do tell me in the comment so I can fix it)
- Interpret Nacker and Concini before Submit Conclusion
➥ Stealthily follow the couriers and after defeating them, the shipment’s delivery point is at the small house north of the waypoint (see the image above).
An Expected Lie
➥ When reaching Nacker’s hideout, the puzzle here is to use the Ball Octopus’ ability on the crystal receiver nodes to move the cube through the rail. Use the crystal on the right when the cube is at the end of the track to block the tracks so the cube won’t reverse back to the beginning. Make sure your view is not obstructed (because you can’t move once you use the Octopus’ ability or it will be canceled).
➥ Once the door to the hideout is open, you can ignore the puzzle. It’s recommended to switch to your best team (especially a Geo character in the team) because you will fight a Meka that has a Geo shield and decent HP. But the more annoying thing is its Geo shield so you should remove it first before brute forcing it.
➥ After defeating the Meka, you can find Nacker on the second floor in the same room. Just climb the wall or use the bubble teleport to find and defeat him. Following this, just follow the quest navigation and you will complete this quest.