Arknights: Endfield — Completing the Echoes of Then Operator Quest

Quick answer: Complete the Cradle of Ages main mission, then interact with the Protocol Singularity aboard the OMV Dijiang to start Echoes of Then. Find all four memories in the snowy field, scan for the hidden path, and defeat the five summoned enemies to finish the quest.

Interact with the Protocol Singularity aboard the OMV Dijiang to start Echoes of Then | Image credit: *Gryphline (via YouTube/@ZaFrostPet)*

How to unlock Echoes of Then

Echoes of Then is the first subquest in Laevatain’s Operator Mission chain, called “Let the Fire Consume the Ashen Past.” It belongs to the Laevatain – Act 1 chapter and is classified as an Operator Side Mission. The quest becomes available only after you clear the Cradle of Ages main mission during Chapter 1, Process 3. Once that mission wraps up, head to the OMV Dijiang and meet Perlica in the Stasis Core to kick things off.

Inspect the Protocol Singularity

Inside the OMV Dijiang’s Control Nexus, interact with the Protocol Singularity. Confirm the prompt, and you’ll be teleported into a snowy landscape. The entire quest plays out inside this instanced area, so make sure your party is ready before entering.

Interact with the Protocol Singularity and you’ll be teleported into a snowy landscape | Image credit: *Gryphline (via YouTube/@ZaFrostPet)*

Travel with Laevatain and clear the first enemies

Exit the cave you spawn in. Outside, Laevatain is already fighting an Aggeloi. After a short dialogue where she offers to help you escape, she joins your party as a trial companion. Push forward along the path and defeat the enemies that appear. They’re standard Aggeloi — nothing that requires special preparation if your gear is at an appropriate level for this point in the story.

All four memory locations

After clearing the initial enemies, you need to locate four hidden memories scattered around the snowy field. Each one triggers a short scene when collected.

Memory	Directions
1	Go straight through the tunnel entrance ahead. The first memory is immediately visible at the end.
2	Turn back from Memory 1, then take a right. This memory is surrounded by flames and guarded by enemies — clear them before interacting.
3	From Memory 2, take two consecutive rights. Look for a distinctive three-sword structure; the memory sits at its base.
4	From Memory 3, turn right again. You can go either left or straight from there — both paths converge on the final memory.

After the first two memories, the quest navigation marker activates and can guide you to the remaining two if you prefer not to explore manually.

You need to locate four hidden memories scattered around the snowy field | Image credit: *Gryphline (via YouTube/@ZaFrostPet)*

Scan the area and follow the golden trail

Once all four memories are collected, use your scanner. A yellow line will appear on the ground, tracing a path toward a hidden entrance. Follow it until you reach a large open battlefield filled with frozen structures and embedded swords.

Defeat the summoned Aggeloi

A cutscene introduces Laevatain’s Other Half, who summons a wave of enemies. There are five Aggeloi total in this encounter. Defeat all of them to trigger the final dialogue sequence with Laevatain. Once the conversation ends, you’re automatically returned to the OMV Dijiang, where you’ll debrief with Perlica. She begins investigating the encounter, and the quest completes.

There are five Aggeloi total in this encounter | Image credit: *Gryphline (via YouTube/@ZaFrostPet)*

Quest rewards

Reward	Quantity
T-Creds	4,250
Protoprism	1
Intermediate Combat Record	1
Arms INSP Set	1

Known bug and fix

Some players encountered a bug shortly after launch where the quest would get stuck on “viewing the Protocol Singularity” after completing the instanced area. The developers acknowledged the issue on the official known issues page and deployed a fix. If you’re still experiencing this problem, try using the in-game unstuck feature first. If that doesn’t resolve it, submit a support ticket — the underlying cause has been patched, and the quest should now complete normally for all players.

Echoes of Then is a relatively short but narratively rich quest that doubles as a trial run for Laevatain. Finishing it opens the path to the next subquest in the “Let the Fire Consume the Ashen Past” chain, so it’s worth completing as soon as it unlocks after Cradle of Ages.