Welcome to the Universe; or, How I Learned to Appreciate the Significance of a Thorough DeFlocking

Welcome to the Universe picks up where Welcome to the Galaxy left off.
Because of the fortuitous discovery that Humans are the only other species in the galaxy immune to the deadly effects of Flock, the catalyst that makes interstellar travel possible, they are now building stardrive engines on Mars for the Galactic Association of Stardrive Manufacturers and Engineers (GASME).
But the Utaalks, a race of lobster like creatures who were the first to claim the same immunity, are incensed at losing their manufacturing monopoly and scheme to sabotage the Martian factory.
Meanwhile, a clandestine military operation has been dispatched from Earth to a remote planet to test the use of Flock as a weapon of mass destruction. If the demonstration succeeds, humans will hold the key to claim dominion over the entire galaxy.
The unintended consequence of the mission is the first encounter of Humans with their long lost cousins, the Smez, the original inhabitants of Mars.