An Expected Plan & An Expected Lie Genshin Impact Fontaine 4.2 world quest guide

This is a short sequel to the Fontaine Research Institute Chronicles with a surprise, some primogems, and an achievement.


‘An Expected Plan’ and its follow-up quest, ‘An Expected Lie,’ are sequels to the Fontaine Research Institute Chronicles main world quest of Genshin Impact. While the prequel is a much bigger quest, these two quests are relatively easier to complete as most of them comprise dialogues with only one association game.

There are also no secret pathways to take, as the entirety of the quest is marked for you. All you need to do is go to the marked locations to progress through the quest.

An Expected Plan

Once you’ve completed the Fontaine Research Institute Chronicles, you will get a new world quest at the Lumidouce Harbor.

The world quest marker will only show up here after you’ve completed the Fontaine Research Institute Chronicles.

You will see a woman wearing glasses named ‘???’ at the harbor, who you can talk to to initiate the quest.

After speaking to the woman, you learn that her name is Fusilier.

Shortly after, Raimondo arrives, and both NPCs will explain the dangers associated with the Arkhium Kinetic Core ever since the explosion that occurred during the Fontaine Research Institute Chronicles world quest.

Once the dialogue is complete, you must take the elevator to the lower level of the Lumidouce Harbor.

Taking elevator to the lower level of Lumidouce Harbor.
Lower level of the Lumidouce Harbor.

When you reach the lower level, you will encounter some suspicious people.

Keep moving to the blue marker until the suspicious people spot you and initiate a fight.

A fight between you and Chaussivert will start. Defeat him to continue with the quest.

After the fight, you and Chaussivert clear the misunderstanding.

After the fight, follow Chaussivert back to his ship.

Use the Lumidouce Harbor teleport waypoint to get back up to the upper level.

You and the company will then make your way to The Rusty Rudder. When you arrive at The Rusty Rudder, you need to find Covault.

Go on the right side (west) of The Rusty Rudder wrecked ship to find a passed-out “Drunkard.”
This “Drunkard” is actually Covault.

Pro tip: you can also speak to the Pitot, the Tavern’s owner, to find Covault, which is probably the “canon” way of finding him.

When you get close to him, a cutscene will initiate, after which Covault will wake up and start fighting you.

You need to defeat him to subdue him.

Once you’ve successfully defeated Covault, he is returned to the ship. After talking to him for a bit, you return to the shore to go to the drop-off point mentioned by Covault.

Following Covault to the supposed “drop-off point.”

Keep following Covault for a bit, and he will eventually stop and attack you together with his mutineers.

Defeat them and return to the ship.

When you return to the ship, an association game will begin where you must associate different elements to come up with the correct outcome.

Association game.

This is how you can solve this association game successfully:

  1. Interpret ‘The transported Nacker’
  2. Interpret ‘The major buyer from Snezhnaya’
  3. Interpret ‘Chaussivert, the Shadow over Lumidouce Harbor’
  4. Interpret ‘Loillier’s boss’
  5. Associate ‘The transported Nacker’ with ‘Loillier’s boss’
  6. Submit ‘Nacker and Concini’ as conclusion.

Once submitted, you need to go to the real drop-off point. When you go to the next marker, you will get a cutscene, after which you must follow two couriers until they arrive at their camp.

Following the two couriers with the shipment.

When you get to the camp, another fight will initiate.

Defeat the treasure hoarders and continue following the blue quest marker.

You will eventually reach the delivery point, which is a secluded house.

Secluded house, which is the shipment drop-off point.

To everyone’s surprise, Edwin Eastinghouse, who was supposed to have died during the events of the Fontaine Research Institute Chronicles world quest, comes out of the house.

Edwin Eastinghouse comes out of the house.

After the dialogue ends, you get the location of Nacker from Edwin, which concludes the ‘An Expected Plan’ world quest. As soon as this quest finishes, the ‘An Expected Lie’ world quest immediately starts right after.

An Expected Lie

You need to go south of Fort Charybdis Ruins, as marked by the quest marker.

Nacker’s location marker.

Continue following the quest marker, which will take you to an underwater ruin with a locked door.

Underwater ruin locked door.

To open the door, you need to solve a quick puzzle. First, go to the left side (northern direction) of the door and equip the Xenochromatic Ball Octopus’ ability.

Xenochromatic Ball Octopus.

Return to the locked door and you should notice an orange crystal mechanism. Hit it to unseal the locks around the border of the door.

Orange crystal mechanism the seals or unseals the locks around the door.

Now, use the Ball Octopus’ ability on the valve to move the cube from the left side of the door all the way to the right side.

Cube brought all the way to the right end of the frame.

Once the cube is on the right end of the door, quickly hit the crystal mechanism again to lock the seals around the door and prevent the cube from returning to its original position, the left side.

Wait a few seconds, and the door will open up. This quest is also important as one of the Fontaine Legends only spawns in here once you’ve completed it.

Go through the water barrier to enter the ruins.

Make sure you switch to either a Claymore character or a Geo character. This is because you will have a boss fight now, and this boss has a Geo shield that can only be destroyed with heavy attacks.

The quickest way to destroy its shield is by using a Geo character such as Noelle, Itto, or Zhongli.

This boss is similar to the Automated Supercomputing Field Generator Fontaine Legend you find in the Overworld.

Once ready, proceed deeper into the ruins until you get a cutscene.

After the cutscene, an Arkhium Kinetic Field Generator called Server-Type Gev003 will spawn

First, use your Geo character to destroy the boss’ shield. Once the shield is down, use your main DPS to deal as much damage as possible.

The boss will take increased damage when the shield is down.

Nacker will spawn on the platform above you when the machine boss is defeated. A water teleporter will spawn by you.

Use it to get to Nacker and eliminate him as well.
Nacker on the platform.

After some dialogue, you must return to Edwin’s house to rejoin Lemarcq.

Fusilier meets up with both Edwin and Nacker here.

Finally, the party returns to the Fontaine Research Institute, where they meet with Raimondo and Choiseul.

After a short dialogue, the quest concludes.

You get 80 primogems from both quests combined and an achievement called ‘A Predictable Ending.’

‘A Predictable Ending’ achievement.
Hassan Sajid
Hassan Sajid // Articles: 728
With lifelong gaming experience across platforms and genres, Hassan creates meticulously researched guides to help both veteran and new gamers by offering in-depth insights and strategies for all aspects of gameplay. // Full Bio