The overarching mystery behind the vanishing scientists is revealed not to be a Napoleonic state operation, but the secret initiative of Rodrigue and Chimène, two monitor lizards endowed with intellect, speech, and longevity by Gustave Franklin’s primitive 1870 serum. Operating from a massive subterranean biosphere, they abducted top researchers to construct an ark-like spacecraft designed to transport Earth’s species to another planet away from human pollution.
A critical divergence separates the reptilian leaders: while Chimène genuinely seeks an ecological haven, Rodrigue is consumed by misanthropic malice. He secretly tampers with the launch to deploy toxic warheads onto the surface, intending to wipe out all humans and inherit the globe. Inside the biosphere, April discovers her abducted parents alive, coerced into perfecting the life serum so the ark’s biological payload can survive cosmic radiation.
When April, Julius, and Pops breach the complex, they expose Rodrigue’s betrayal to Chimène. The conflict turns deadly as Rodrigue murders Chimène and triggers the countdown. Darwin, having received April's completed serum, heroically throws himself into the central reactor chamber, using his invulnerable, serum-saturated body to neutralize the bio-weapons and guarantee the payload's safety. The ark successfully blasts off, and the subterranean facility collapses, forcing all abducted scientists back to the surface world.
The Epilogue: The return of the world's greatest thinkers dismantles the imperial monopoly on fossil fuels, ushering in clean electrical grids and green energy. Decades later in 2001, an elderly April and Julius watch live coverage of a lunar landing mission, which reveals that the 1941 rocket successfully terraformed space into a lush forest—where an immortal, thriving Darwin is seen happily lounging among the alien foliage.