Subnautica: Below Zero story recap

Subnautica: Below Zero (released May 14, 2021) is set two years after the events of the original Subnautica. It follows Robin Ayou, a scientist who travels to Planet 4546B to investigate the death of her sister Sam.

Robin's arrival

Robin smuggles herself onto the planet without Alterra Corporation's knowledge. Her official cover is as a researcher at Alterra's station in Sector Zero, an arctic region of Planet 4546B. Alterra has returned to the planet after Ryley Robinson's departure and established a research outpost. The Vesper, an Alterra orbital station, monitors operations from geosynchronous orbit, periodically demanding progress reports from personnel on the surface.

Sam's death

Sam Ayou was a roboticist at Alterra's Sector Zero research station. She discovered that Alterra had found a frozen leviathan in the Glacial Basin still infected with the Kharaa bacterium and was studying the pathogen for potential bioweapons applications.

Encouraged by Marguerit Maida (the Degasi survivor from the first game, who had drifted to Sector Zero and built a hidden base beneath the Lilypad Islands), Sam took action. She synthesized a cure using Enzyme 42 and stashed it, then set explosives to collapse the cave housing Alterra's Kharaa specimens at the Phi Excavation Site. Both Sam and security guard Parvan were killed in the resulting cave-in. Alterra covered up the circumstances, ruling Sam's death as "employee negligence."

The Frozen Leviathan

The Frozen Leviathan is a massive creature trapped inside a wall of ice at the Phi Excavation Site in the Glacial Basin. Alterra had built corridors and catwalks around it for research access. The creature is infected with Kharaa. Players can eventually use Sam's hidden antidote cache to cure the leviathan, completing her unfinished mission.

Al-An

While exploring an Architect facility, Robin accidentally downloads Al-An, an Architect consciousness, into her brain. Al-An was a lead scientist who had disobeyed his species' orders by attempting to hatch Sea Dragon leviathan eggs, causing the facility's destruction and triggering the Kharaa outbreak on 4546B centuries earlier.

Al-An is stuck in Robin's head because his physical body was destroyed. The two develop an uneasy partnership over the course of the game. Robin learns about Architect society, their technology, and their relationship with the Kharaa bacterium through conversations with Al-An while they explore Sector Zero together.

Building Al-An's body

Robin constructs a new physical body for Al-An using Architect technology scattered across Sector Zero. The body requires three components, each found at a different Architect Cache site:

• Architect Organs Found in the Crystal Caves Cache, stored in an open container.

• Architect Skeleton Found in the Deep Lilypads Cave Cache, in front of an Alien Statue.

• Architect Tissues Found in the Arctic Spires Cache, buried under collapsed rubble.

Once collected, Robin fabricates the complete vessel at the Fabrication Facility deep in the Fabricator Caverns, accessed through the Crystal Caves.

Marguerit Maida

Marguerit is a Trans System Federation veteran and mercenary who was originally hired by Paul Torgal to guard the Degasi. She was one of three Degasi crash survivors (with Paul and his son Bart) and the only one still alive a decade later. She likely survived the Kharaa infection through bioaccumulated Enzyme 42 from the Reaper Leviathan she fought.

By the events of Below Zero, Marguerit has built a base below the Lilypad Islands and maintains a greenhouse on a nearby iceberg. She is hostile to Robin at first but gradually assists her. She was the one who encouraged Sam to sabotage Alterra's Kharaa research, making her indirectly responsible for both Sam's and Parvan's deaths.

Resolution

Once Al-An's new body is complete, he transfers out of Robin's brain and into the physical form. He decides to return to the Architects' homeworld. Robin, having burned her bridges with Alterra, chooses to travel with Al-An rather than return to human space. The game ends with them departing 4546B together.

The story rewrite

Below Zero's story underwent a complete overhaul partway through Early Access. In November 2019, Unknown Worlds announced they were scrapping the original narrative and hiring writer Jill Murray to start fresh. The team stated they had struggled to "define characters' motivations early and build key relationships."

The original Early Access story kept Sam alive aboard the Vesper orbital station, with Robin stationed on the planet surface. The rewrite killed Sam before the game begins and shifted Robin's motivation from a routine research assignment to a covert investigation into her sister's death. The change to a voiced, opinionated protagonist was itself controversial within the community. Voice actress Kimberly Brooks replaced the original Early Access performer Tala Gouveia, who was unavailable to return.

Development notes

Below Zero was originally planned as DLC for the first Subnautica but was expanded into a standalone game. It entered Early Access on January 30, 2019 and launched in full on May 14, 2021. Like the original, it was built in Unity.