A Walkthrough Companion: Unlocking Hidden Routes in the Moon Game Lunar Arc
The Lunar Arc has three routes the in-game flowchart never shows you, and one of them rewrites the prologue in retrospect. A spoiler-light companion to the choices that matter and the ones that quietly do not.
The Lunar Arc — the back half of the second season of the Moon Game canon — is structurally the most ambitious thing the property has shipped. It also has the most opaque route geometry in the catalog. The in-game flowchart shows you six routes. There are nine. One of them rewrites the prologue in retrospect, and most readers complete the arc without ever knowing it exists.
This piece is a spoiler-light companion. The aim is not to tell you what happens; it is to tell you which choices are doing real structural work, which ones are atmospheric, and how to actually reach the three hidden routes the flowchart will not show you. If you have not finished the visible six yet, bookmark this and come back. The hidden routes are designed to be unreachable on first playthroughs, and the writers built that constraint in deliberately.
The Lunar Arc’s flag system, briefly
Lunar Arc uses a hybrid flag system: a standard heroine-affection counter for the visible routes, plus a separate “lunar phase” state machine that tracks which version of the prologue is being played in retrospect. Most readers never notice the second system because it operates in the background. The hidden routes require triggering specific lunar-phase transitions before specific affection thresholds are crossed.
Practically, this means the order in which you play the visible routes matters for hidden-route access. The game does not warn you about this.
The visible six (briefly)
Without spoilers, the visible routes are:
- Akari’s route — accessible from the main menu after the prologue. The most reader-friendly entry point and the canonical first playthrough.
- Mei’s route — unlocked after completing Akari. Treats the events of Akari’s route as having happened and references them obliquely.
- The Twins (Yui and Hana) — paired route, unlocked after Mei. Has two endings depending on a single chapter-twelve choice.
- Reina’s route — unlocked after Twins. The longest of the visible six and the one most readers consider the “true” route on first reading.
- Tomoko’s route — unlocked alongside Reina but not advertised. The flowchart shows it as a side route. It is not.
- Suzu’s route — unlocked after Reina and Tomoko. Most readers stop here. The arc appears to end. It does not.
If you finish all six and stop, you have read about 70% of the Lunar Arc by word count. The remaining 30% is in the three hidden routes.
Hidden route 1: the Caretaker route
How to unlock: During the prologue, when the choice “Stay at the shrine” appears at the end of chapter two, choose it. Then in chapter four, decline the festival invitation. Then in chapter seven, when Suzu offers to walk you home, agree but ask about her grandmother. This sequence triggers a lunar-phase transition that opens the Caretaker route after you complete Suzu’s visible route.
What it is: A reframing of the prologue events from a perspective the visible routes never grant access to. The Caretaker route reveals that one of the secondary characters has been driving plot events the protagonist attributed to coincidence. It does not introduce a new heroine; it makes you re-read the heroines you already met.
Why it is hidden: Because the route’s emotional impact depends on the reader having first formed strong opinions about the visible cast. Playing it first would defang the reveal. The writers gated it deliberately.
Length: About 8 hours. Roughly the length of Akari’s route.
Hidden route 2: the Negative-Space route
How to unlock: This route is reached by deliberately failing the visible routes in a specific way. Across three separate playthroughs, decline the route-lock confession in the chapter-fifteen midnight scene. The third declination triggers a different lunar-phase state and opens the Negative-Space route from a previously inaccessible main-menu option.
What it is: The route the protagonist takes when the protagonist refuses to choose. It is shorter than the others, harder-edged, and contains the only ending in the arc that the writers themselves have publicly described as “the one we are most proud of.”
Why it is hidden: Because the route exists to reward readers who treat the medium with enough attention to notice what the standard route geometry is asking of them. It is, in effect, the writers’ acknowledgment of readers who push against the genre’s defaults.
Length: About 6 hours. Dense.
Hidden route 3: the True Lunar route
How to unlock: After completing all six visible routes, the Caretaker route, and the Negative-Space route, return to the main menu. A new option will appear under the prologue. This is the True Lunar route.
What it is: The arc’s true ending. It synthesizes the events of all eight prior routes into a single coherent narrative that explains why the lunar-phase system existed in the first place. The reader who reaches it is the reader who has spent roughly 80 hours with the cast, and the route is calibrated for that reader specifically.
Why it is hidden: Because exposure to it before earning it would compress and cheapen the synthesis. The True Lunar route is the longest route in the arc and the only one the writers have stated is meant to be played exactly once.
Length: About 14 hours. Plan accordingly.
What makes the Lunar Arc’s geometry worth this much trouble
It is fashionable in genre criticism to dismiss elaborate route-gating as gimmickry. With Lunar Arc the gating is structural rather than decorative — the geometry encodes the arc’s thesis about choice and consequence, and a reader who skips to the True Lunar route via guide cheats is reading a different (lesser) work than a reader who earns it. The gating is the point.
If you have finished only the visible six, you have read a good adult VN. If you finish the three hidden routes in the intended order, you have read one of the most carefully constructed routed narratives the medium has produced this decade. The work is there. It just expects you to find it.
For readers who want deeper notes on the lunar-phase state machine, the structural reasoning behind specific choice gates, and the unreleased developer commentary on the True Lunar route’s scrapped earlier draft, the longer-form material lives in the members area. It is the kind of writing that does not survive the public-facing storefront descriptions intact.