Chapter 19

Chapter 19 — "Taumoeba"

TL;DR: The Adrian sample contains a microscopic predator that devours Astrophage — Grace names it Taumoeba — but they discover, almost immediately, that nitrogen kills it.

Summary: Under the microscope the Adrian sample is alive. Tiny amoeba-like organisms swim in the ochre dust, and when Grace introduces a single Astrophage into the slide, the Taumoeba (his immediate name for it: "Tau Ceti amoeba") swarms it and devours it within seconds. This is the answer. This is why Tau Ceti is uninfected — its system is naturally seeded with the Astrophage's predator. Grace and Rocky's elation lasts about an hour. Routine compatibility tests reveal the catch: Taumoeba cannot survive in nitrogen-rich atmospheres. Earth's air is 78% nitrogen. Erid's air contains 8% nitrogen. The cure is real, but in its current form it cannot be deployed at either home world.

Key scenes:

• A microscope slide rendered as a wide visual: an Astrophage cell being engulfed and dissolved by amoeba-like organisms
• Grace writing "TAUMOEBA" on the lab whiteboard with marker
• A cheerful Rocky-and-Grace high-five-equivalent — a tap-rhythm against the sphere
• The crushing chart on a second whiteboard: nitrogen-tolerance plotted against Taumoeba viability, falling sharply

Characters present: Ryland Grace, Rocky

Locations / settings:

• The Hail Mary lab — microscope station, whiteboards, sample chambers

Visual motifs: the microscopic kill rendered as a hard graphic — a black Astrophage being unmade by a swarm of small pale shapes; a triumphant whiteboard with a single new word; a second whiteboard with a plummeting nitrogen-tolerance curve in red against gold; the lab whirring quietly around them

Emotional tone: triumphant, then crushed, scientifically alert, focused

Confidence: high — the Taumoeba reveal and the immediate nitrogen-tolerance problem are pivotal.