How to open the sealed door in Genshin Impact An Expected Lie quest

An Expected Lie is part of a new quest series that is a sequel to the Fontaine Research Institute Chronicles in Genshin Impact. During the quest, you are tasked to find the secret hideout of an NPC named Nacker in Fort Charybdis Ruins.

As you get closer to his hideaway, you find an underwater ruin and get an objective to open the sealed door. To do so, you must solve a simple puzzle using Xenochromatic Ball Octopus' ability.

After opening the sealed door, you must defeat Nacker and rejoin Lemarcq to report everything to Fontaine Research Institute. This is a guide on how to open the sealed door in Genshin Impact's An Expected Lie World Quest.

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Genshin Impact An Expected Lie: Open the sealed door quest guide

Solve the puzzle to open the sealed door (Image via HoYoverse)

To get the Open the sealed door objective in Genshin Impact's An Expected Lie World Quest, follow the navigation and teleport to the southern waypoint in Fort Charybdis Ruins and dive underwater. You will find a large door southeast of the Tower of Gestalt, and a few lines from Paimon will appear on the screen once you get closer to it.

As mentioned earlier, you need to solve the puzzle in front of the door to open it. You can start by swimming toward your left to find a Xenochromatic Ball Octopus and copy its ability. Once that is done, head back to the door and hit the pneumousia crystal once so that it becomes blue.

Next, aim at the valve using the Xenochromatic Ball Octopus' skill and move the block on the door's frame until it reaches the other end.

When the block starts rising back up, you need to hit the pneumousia crystal again when it is at the same level as the stone carving next to the door, as demonstrated in the GIF above.

Timing it right can be slightly difficult since the block moves fast, but you can keep trying until you get it right. Once done, the door will open, and you will get the next objective, which is to find Nacker inside the ruin.

A brief cutscene will trigger as soon as you head inside the door. After this, you must keep moving ahead until you find Nacker.

Note that you will encounter a couple of difficult enemies like the Arkhium Kinetic Field Generator, so it is advised to bring a Geo unit or a Claymore user to break its shield.

Finally, defeat Nacker as well and rejoin Lemarcq.

Quest completion reward (Image via HoYoverse)

Completing An Expected Lie quest in Genshin Impact will reward you with 40 Primogems and an achievement - A Predictable Ending.