In a pre-mission flashback, the Hail Mary crew and assembled scientists watch a critical ISS-bound launch carrying the cockpit, lab, and dorm modules. Amid banter about Stratt, Commander Yáo bluntly confirms that Ryland Grace is effectively the project’s number two, setting expectations for Grace’s leadership role.

Back at Adrian, Grace’s lab attempt to spike a predator bloom in a low-pressure Adrian-atmosphere bulb fails, showing no Astrophage decline. He and Rocky reason the predator likely lives where Astrophage breed. Using the Petrovascope and geometry, they map bright IR “clouds” and determine a narrow breeding layer at 91.2 km altitude, less than 200 meters thick.

They must sample that layer, but orbital constraints block easy options: dropping lower risks burn-up, and firing the spin drive in air would create catastrophic plasma. Grace proposes “fishing”: hang a 10 km xenonite chain with a sampler while thrusting 30 degrees off-vertical so exhaust misses the chain. At ~100 m/s lateral speed, the chain should survive, deflecting only ~2 degrees. Grace mills molds for interlocking links; Rocky urges mass production but Grace refuses melting ship parts.

Discussing fuel, Rocky explains Erid’s easy Astrophage breeding in superheated oceans and recounts baffling trip anomalies—normal thrust but odd speeds and distances, an early halfway point, arrival in three years ship-time, and huge fuel reserves. Grace realizes Eridians lack relativity; their Newtonian planning caused the paradoxes and overfueling. He prepares to teach Rocky the correct physics.

Another flashback brings Steve Hatch, who unveils autonomous “beetle” return probes: spin-drive craft with star-tracker navigation, reaction wheels, onboard power, and about 125 kg of Astrophage fuel, capable of 500 g to 0.93c and a ~12-year Earth-frame return (about 20 months proper time). He requests test Astrophage, radiates optimism, and names the probes after the Beatles.