This article is about the moon Alpha. You may be looking for the settlement within the shield.

Alpha, also called Sanctum, is a moon sharing atmospheric similarities to Earth. It is located in the Goldilocks zone of a binary star system, meaning it is in the habitable zone and has two suns. It was colonized by a team from Earth made up of four families, the Primes. Using Mind Drives, they continued their rule here for over two centuries.


The atmosphere is similar to Earth's, containing 77% nitrogen, 22% oxygen, 0.5% of argon, 0.2% of carbon dioxide, and small amounts of a new, unidentified element. Due to having two suns, it was believed that the moon's surface has higher radiation levels than pre-apocalypse Earth. To counteract that, Eligius Corporation used the Nightblood serum on the members of Eligius III going to the moon. However, Nightblood was later discovered to be unnecessary for the survivors of the Battle for Eden, since the radiation levels are revealed to be good.


In 2045, Eligius III arrived to this moon. The Eligius Corporation was looking for a source to tap for oil, since Earth's oil reserves had run dry. The crew had underwent the blood alterations from Becca Franco's Nightblood serum, in case the radiation levels were too high. According to Eligius IV's records, if they ever reported back, it was after Apocalypse One, when no one could have received the call. The true results of their arrival remain unknown.

Centuries later, Monty Green, after 30 years of research, cracked the code-locking on the Eligius III files while on Eligius IV, and set the mothership's coordinates to travel to the new planet (not yet identified as a moon). The ship's journey lasted 75 years. Upon arrival, Monty and Harper McIntyre’s son Jordan Green woke from cryosleep as his father intended. He went on to follow his father's instructions and woke Clarke Griffin and Bellamy Blake. He shows them his father's video files, explaining their life on the mothership, the destroyed status of Earth, and the new world they could call home.

Celestial Events

Red Sun Eclipse

601 Red Sun Eclipse cropped

The moon undergoes a celestial event in which the two suns eclipse, triggering the release of a psychosis-inducing toxin from the plants. During the eclipse, sonic anomalies are sometimes caused by molecular vibrations in the air and trees. When exposed to the toxin, all fauna are affected and goaded into violence. Those killed after the eclipse is over are consumed by the plants and trees. This celestial event is known as the Red Sun. According to Gabriel Santiago, Josephine Lightbourne theorized that these events are why higher lifeforms never evolved on the moon.

In "What You Take With You," Gabriel uses red sun toxin to help Octavia remember her time in the anomaly. According to Gabriel, he and Russell Lightbourne once used the toxin in a similar manner to determine if any of the host's mind survived after the implantation of a Mind Drive. The answer was no, but in doing so, they unlocked parts of their own minds, things they'd hidden from themselves, answers about what their greater purpose was. In "Ashes to Ashes," Gabriel explains to Clarke and Bellamy that the toxin is everywhere: in every leaf on every tree, in the soil and the rocks. Over time, the Primes had found other ways to harness its power. Simone weaponized it as part of her Adjustment Protocol while Gabriel focused on developing an anti-toxin.

Temporal Flare

605 Temporal flare

A temporal flare seems to be a green light source in the sky shoots out other green flares that burn and destroy anything they touch.

In "The Gospel of Josephine", Xavier notices a Temporal Flare going on. He tosses Diyoza a rope and tells her and Octavia to get out and run. Diyoza gets out, but she realizes that Octavia has no time. She tells her she will return. Octavia submerges herself in the quicksand like stuff and survives the Temporal Flare. Diyoza manages to dig Octavia out and they run after Xavier.

The Anomaly

S6 title sequence intro - The Anomaly crop

The Anomaly as seen from space.

The Anomaly, also known as the Temporal Anomaly, is the source of the temporal flares. It was originally thought that Gabriel Santiago went through this Anomaly. The Anomaly has also sent messages to Diyoza, Octavia, and Gabriel Santiago himself.

In the "The Old Man and the Anomaly", it is revealed that the radio signals get absorbed by the Anomaly and retranslates in The Verge, where it's possible to pick them up here in endless, repeating waves. It is also revealed that the Anomaly does the same as the Red Sun and that the Anomaly has similar effects on plants, only it's "constant and weirder". The Anomaly gets into people's minds, causing them to hear things and hallucinate, sometimes their darkest fear, their deepest desire, and both at once.


Native lifeforms are largely floral in nature. Nearly all existing faunal creatures were classified by Josephine Lightbourne in four evolutionary branches: Insect, rodent, reptile, and the less easy to identify, coined "Guaiwu" ("freaks" in Mandarin).


S6Titles Bug

A bug

In "Sanctum", Jackson can be seen with a native bug contained in a jar. Soon after, a swarm of the bugs attacks and chases the exploration team through the radiation shield, into a settlement.

The bugs appear to be omnivores, shown to eat both meat and plants, as observed by Jackson. The bugs travel in swarms when hunting. They also appear to be strong, the bug Jackson had trapped repeatedly slamming into the glass without injury. The bugs avoid fire. 

The bugs have hook-like legs and round eyes, like that of a fly. They have a small tail and hidden antennae.

Snake (Kepa-She)

Kepa-She 603

In "The Children of Gabriel", there appears to be a hideous snake, "Kepa-She" in Chinese. It can degrade the poison from a body, caused by being exposed to the seaweed during the eclipse.


During Red suns, seaweed can move around ponds or lakes and crawl into someone like a tapeworm. It releases a toxin within the victim, practically killing them. The person can be revived by the Kepa-She snake like John Murphy was.

In "The Children of Gabriel", during the red sun, seaweed crawled into Murphy when Bellamy almost drowned him in the pond in the village. Cillian lets the Kepa-She bite Murphy, reviving him.

Trees and other plants

Alpha's forest 2

During the red sun, trees and other types of growth become dangerous as they can release a toxin making people and bugs psychotic. If a victim dies near plants, the plants will "consume" the dead, even if there is no red sun. They can also eat fauna and bugs. The Offering Grove is a place where people give human sacrifices to trees.

Tree Sap

606 Tree sap cure

After a Temporal Flare, the sap in remains of fossilized trees becomes "mutated" and can heal any sort of wound when applied on.



Other Sanctum Citizens

  • Blythe Ann
  • Jae
  • Delilah
  • Rose
  • Jade
  • Cassius
  • Sierra
  • Gavin
  • Josiah
  • Brooke
  • Alejo
  • Tyman Averi
  • Annabel Averi
  • Savannah
  • Isaac
  • Miranda's lover
  • Tai
  • Arabel

Children of Gabriel




Sanctum (Settlement)

Main article: Sanctum (city-state)
Sanctum settlement 6x01

The settlement, also called Sanctum.

The Sanctum settlement is located within the radiation shield. It was built to be a sanctuary for human race. The radiation shield protects Sanctum Citizens from intruders, dangerous lifeforms as well as the adverse atmospheric conditions on the moon.

Ryker's Keep

Back in the early days, Ryker built a temporal place inside the cave system under the settlement. The purpose was to hide there during the Red Sun Eclipse, so neither citizens or Primes would be exposed to it.

Offering Grove

606 Offering Grove

Offering Grove

The place in the woods near the settlement which serves as a cemetery for the dead Sanctum citizens. According to traditions, the bodies are offered to the trees, so their souls could be in a better place.

The Verge

6x08 TheVerge

The Verge

The Verge is one of the other 14 research outposts built by the colonists for their research experiments. Currently it's used by Gabriel Santiago as a transit point in the woods.

Due to it's location near the border of the Anomaly, all radio signals get sucked up by it and retranslates here where it's possible to pick them up here in endless, repeating waves.

C.O.G. Territory

609 COG territory

The cave systems, where the Children of Gabriel live.

The Children of Gabriel Territory is home to a militant faction of rebels, known as the Children of Gabriel. They live in caves and other locations as well.


Season Five
Episode Appearance Status
Red QueenAbsent
Sleeping GiantsAbsent
Pandora's BoxAbsent
Shifting SandsAbsent
Exit WoundsAbsent
Acceptable LossesAbsent
How We Get to PeaceAbsent
Sic Semper TyrannisAbsent
The Warriors WillAbsent
The Dark YearAbsent
Damocles (Part 1)Absent
Damocles (Part 2)Appears
Season Six
Episode Appearance Status
Red Sun RisingAppears
The Children of GabrielAppears
The Face Behind the GlassAppears
The Gospel of JosephineAppears
Memento MoriAppears
The Old Man and the AnomalyAppears
What You Take With YouAppears
Ashes to AshesAppears
Adjustment ProtocolAbsent
The Blood of SanctumAbsent

Notes and Trivia

  • Before finding out that Alpha is a moon, it is erroneously referred to as "Planet Alpha".[1]
  • Jason Rothenberg stated that aliens will be introduced on this world.[2]
  • Season Six is set on this world.[2]
  • Rothenberg said that we will learn more about Eligius III and when it came to this world.[3]
  • This particular place in "Goldilocks Zone" refers to the world being far enough away from its sun to contain liquid, but still close enough to sustain life.
  • Sanctum is the Latin root of "Sanctuary".
  • The moon will appear in Season Seven.


  • The moon and the planet it orbits
  • Raven watching Gagarin descent to the moon surface

  • The beautiful scene on the world.
  • The landscape on the world.
  • Alpha's landscape

  • Kepa-She
  • Kepa-She
  • Lifeforms in research studies
  • BTS - dead bug
  • This tree sap can heal wounds.


Start a Discussion Discussions about Sanctum (moon)

Community content is available under CC-BY-SA unless otherwise noted.