Arknights Wiki
Main Theme.png

Main Theme, formerly known as Main Story, is the "campaign mode" of Arknights.

Currently the Main Theme is divided into three story arcs: Act 0: Hour of an Awakening, Act I: Shatter of a Vision, and Act II: Shadow of a Dying Sun, which consists of 150 main operations, 26 interludes (5 of which are secret and must be unlocked by fulfilling specific conditions in certain main operations), 45 sub-operations, 25 Inferno Mode operations, and 20 tutorial operations, for a grand total of 266 operations.

The Hour of an Awakening and Shatter of a Vision arcs belong to the first part of the Arknights storyline which deals with the Chernobog Crisis, while the Shadow of a Dying Sun arc belongs to the second part which centers on R.I.'s involvement in the Victorian Crisis.


Prologue to Episode 04 were available upon the initial release, with more episodes added over time.

Release dates
Episode CN Global TW
Episode 05 2019/6/9 2020/2/26 2020/8/13
Episode 06 2019/12/24 2020/6/30 2020/12/24
Episode 07 2020/4/25 2020/12/30 2021/5/27
Episode 08 2020/11/1 2021/4/30 2021/8/26
Episode 09 2021/9/17 2022/3/17 2022/6/21
Episode 10 2022/4/14 Mid October 2022 TBA

Act 0: Hour of an Awakening

Prologue: Evil Time Part 1
Episode 01: Evil Time Part 2
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Episode 02: Separated Hearts
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Episode 03: Stinging Shock
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Act I: Shatter of a Vision

Episode 04: Burning Run
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Episode 05: Necessary Solutions
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Episode 06: Partial Necrosis
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Episode 07: The Birth of Tragedy
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Episode 08: Roaring Flare
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Act II: Shadow of a Dying Sun

Episode 09: Stormwatch
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Episode 10: Shatterpoint
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Tuning System

The following information are based on community-provided translations and may not represent the official localization.

From Episode 10 onwards, the game introduces the Main Theme Tuning System, which consists of three components: Combat Environments, the Unsigned Notebook (although the name is probably specific to Episode 10, while the feature will not be), and Undeterred Inspiration.

Combat Environments


A new feature of Episode 10, Combat Environments are essentially a "difficulty setting" for operations. The Combat Environment system allows the player to decide how difficult the operations will be, permitting new players easier access to later Main Theme operations. There are three Combat Environment options: Storyline Experience, Conventional Operation, and Ordeal Ground.

The Environmental Compatibility system

The Combat Environment difficulty options are unlocked by clearing the previous operation' corresponding difficulty option (e.g. 10-5's Ordeal Ground will only be available after 10-4's Ordeal Ground is cleared first), called the Environmental Compatibility system. Environmental Compatibility will automatically set operations to the highest difficulty setting available unless otherwise indicated. Clearing an operation in the higher difficulty retroactively counts as a clear of the lower difficulties as far as rewards are concerned (i.e. clearing Ordeal Ground from the onset will also award the rewards of Conventional Operation and Storyline Experience). However, starting by the Ordeal Ground iteration of the operation will consume double the Sanity.png Sanity, as both the Sanity of the Conventional Operation and Ordeal Ground will be expended at once, similar to a player doing an operation's normal and Challenge Mode versions in a row.


Storyline Experience

An easier experience for the sake of having the story and gameplay of Arknights without some of the more difficult aspects of the game, intended for players who merely seek to engage with the story first, and want to leave more difficult content for a later date, or not at all.

  • Friendly units are buffed significantly.
    • Redeployment cooldown halved.
    • All attributes, except block count, are increased.
  • Only award certain materials as first clear rewards; the usual Originite Prime.png Originite Prime will not be awarded.
  • Does not consume Sanity and no EXP.png EXP will be awarded, but the LMD.png LMD will still be awarded as usual.

Episode 09 operations will retroactively receive Storyline Experience versions upon the release of Episode 10. From that point on, players who have already completed Episode 10 operations prior to their addition may thus access Episode 09 from their Terminal at any time to receive the rewards from the Storyline Experience version of the respective operations.

It is yet unknown, but probable that previous episodes will also receive Storyline Experience similar to Episode 09 in future updates.

Conventional Operation

The normal, baseline difficulty.

This mode is the standard Arknights gameplay everyone knew and love.

Ordeal Ground

Ordeal Ground is functionally similar to and replaces Challenge Mode (at least as far as Episode 10 is concerned), with the following distinctions:

  • The Life Point count is no longer reduced to 1.
  • Costs only one Drill Plan.png Drill Plan for a practice run.
  • No longer halves the Sanity refunded upon quitting or failing, instead refunding 95% of the Sanity spent as with every other operation.
  • Awards the regular, special, and extra drops when cleared, like the Conventional Operation version.
  • Certain operations will have completely different maps and enemies in Ordeal Ground than in Storyline Experience/Conventional Operation instead of having handicap(s), effectively making it a different operation altogether.

Unsigned Notebook

Unsigned Notebook progress is recorded by achieving different Combat Environment stages (if applicable) in the episode, which gives out rewards and additional story content. The Unsigned Notebook is functionally identical to an event's milestone reward system with clear requirements, although unlike an event, it is presumably available permanently.

Undeterred Inspiration

For the first two weeks after a Main Theme episode is released, the Sanity consumed to run the corresponding episode's operations will be fully refunded if the player quits or fails the operation even after the first failure. This applies to both Conventional Operations and Ordeal Grounds, meaning there is no point in using any Drill Plans and the player may try the episode's operations an unlimited amount of times without consequence.

Inferno Mode

The operation start button's appearance for Inferno Mode operations

From Episode 05 onwards, each episode also includes four Inferno Mode operations that are added one week after the release of their corresponding episode, the first of which is unlocked by clearing the episode's last main operation.

Inferno Mode operations can be distinguished by the "H" prefix before the operation's episode and number (e.g. H5-1), which stands for "high difficulty," and are considerably harder than the episode's main operations. They do not award anything aside from an Originite Prime when cleared with 3 stars for the first time and plaques for some, and they do not have a Challenge Mode version.

Unlike previous episodes, Episode 09 was released with three Inferno Mode operations immediately available, with three more added in the following week.

Episode 10 only introduces three Inferno Mode operations one week after its release, and differs from previous Inferno Mode operations where their Combat Environment setting is permanently set to Precipituous Battle in which all of them feature the episode's main boss enemy with additional abilities specific to each Inferno Mode operation.

Episode 05
Episode 06
Episode 07
Episode 08
Episode 09
Episode 10