The Expanse: Osiris Reborn Goes Loud on Ganymede—Stealth Mission Turns into a Firefight

Owlcat Games unveiled a mid-game mission for The Expanse: Osiris Reborn at gamescom, showing players infiltrating a secret Protogen base on Ganymede before the operation descends into combat when a bioengineered creature is released inside the facility.

What Went Down on Ganymede

The gamescom demo, shown during GameStar’s Find Your Next Game showcase, follows the Captain and their twin sibling J as they attempt to recover data stolen from them on Pinkwater station. The pair enter the Protogen base undercover, speak with employees, and work to reach the storage area without drawing attention while the rest of the crew provides support from a distance. The mission plays out through exploration, dialogue, and stealth—until an unexpected third party shows up and releases a dangerous creature into the facility, forcing the siblings to abandon subtlety and fight their way out.

Owlcat demonstrated both a new trailer and extended gameplay footage, giving players a look at how the game blends these mechanics together. Ganymede itself holds significance for The Expanse fans; it’s a major location in the source material, and Protogen sits at the center of the protomolecule experiments that fuel the early books and TV seasons.

Why This Matters

Osiris Reborn is Owlcat’s sci-fi RPG set within The Expanse universe, and the studio has built it with familiar RPG systems in mind. The game draws comparisons to Mass Effect through its third-person combat, ship-based structure, companions, dialogue choices, and customizable protagonist—a formula Owlcat itself has acknowledged. Like the studio’s other work, the game leans on choice and consequence: your Captain can be an Earther, Martian, or Belter, and those decisions shape relationships and quest outcomes. Companions also unlock different options during missions through their unique abilities.

The Exploits mechanic, revealed in March, lets companions contribute directly in combat. You take two crew members into the field, while characters aboard the Gemini can assist remotely depending on their skills. Recruitable companions include Zafar and Michael, among others.

This Ganymede mission sits well into the campaign—notably further along than the Pinkwater 4 mission from the closed beta that began in April, where players first meet Zafar and encounter Protogen on the Captain’s heels.

What’s Next

The Expanse: Osiris Reborn launches in spring 2027 across PS5, Xbox Series X|S, Steam, Epic Games Store, and GOG, with day-one availability on Xbox Game Pass. Players will likely see more mission breakdowns and systems deep-dives as the release window approaches.