The Combatant's Guide To Zyzzlvaria

by Mark Gottlieb and Dan Katz

This puzzle mimics the style of entries in The Hitchhiker's Guide to the Galaxy (the book, not the book about the book). Skipping ahead first to the final entry, three words in each paragraph have had three letter-changes applied to them, as shown:

In a universe where potentially sticky SITUATIONS (SIU) are too often overlooked, the vigilantly WATCHFUL (WTH) eye of Captain Blastoid overlooks nothing. Blastoid has shown no lust for advancement, having turned down the opportunity to become BRIGADIER (BRG) General Blastoid on more than one occasion.
Leah, the Brass Rat's planetologist, can tell a feldspar asteroid from a SANDSTONE (SOE) moon a full light year away. Sadly, she has witnessed the destruction of enough worlds to drive a lesser woman mad; for many races, the world ends with both a bang and a WHIMPER (WMR). It's hard to look at a mother snugly NESTLING (STG) a child in her arms, knowing that at any moment they could both be vaporized by an itinerant comet.
Zoe, the ship's helmswoman, is probably the most well-ADJUSTED (DJU) member of the crew. She spends her nightcycles making sure the navigational beacons hold TOGETHER (GHR) through thick and thin, SWAPPING (WNG) out cables and relays as needed to keep the ship on whatever suicidal course the Captain selects.
Ensign Algernon is fresh out of the Space Academy, a well-regarded school with a generous ENDOWMENT (DOW) from the government. Rebellious in his youth, he was once suspended for SUBVERSIVE (BVR) behavior when he attempted to convince the students to forcibly overthrow the faculty. That phase of his life seems to be over, although he is still occasionally shadowed by REPORTERS (PRT) hoping to get a scoop on his latest controversial action.
Merely comprehending the “brains” of the Brass Rat—to say nothing of actually keeping it running—is Scotchy’s DAUNTING (DAT) task. That's because the Athena Electronic Cortex’s remarkable Self-Iterative Paradoxical Processor gives it the COMPUTATION (COM) power of a hundred Athena Electronic Cortexes. Once he logs into one of the ship's terminals, a simple 1,200-keystroke sequence allows Scotchy to DOWNLOAD (LOD) any file from the central database.
The Brass Rat's xenobiologist, Ralph, has catalogued the vast MAJORITY (MJY) of the strange creatures in Outer Zyzzlvaria, though TRUTHFULLY (RUH), he must admit that a few still elude him. Ralph prefers life among the stars to being a PROFESSOR (ROF) at the Magrathea Institute of Technology, at least since the authorities discovered his experiments.
Ernie is the ship's doctor. It is his responsibility to heal the crew's wounds after their EPISODIC (SOD) adventures, each of which seems to wrap itself up in just under thirty minutes. Out here on the fringe, he sometimes has to be CREATIVE (CRA) with his techniques, improvising when the precise tools are not available. He once removed a three-inch DIAMETER (IME) spherical implant from Scotchy's chest in the middle of a firefight, and the engineer has gotten plastered with Ernie every nightcycle ever since.
Last but certainly not least, there's holoprogrammer Harold. As the Brass Rat’s resident MORALIST (RLT), Harold frequently finds himself WRESTLING (RST) with issues of right and wrong. If the rest of the crew ever waited for him to make up his mind and RECOMMEND (MED) a course of action, they’d never get anything unethical done.

Each of the other 24 entries is a mock Hitchhiker's Guide entry, where one letter has been changed in the title. The old-letter-new-letter pair for each entry is a subset of exactly one of the threesomes of correct letters in the final entry.

The unused letters in each trio, taken in entry order, read WHAT FORTY TWO IS ON THE USAMO. On the United States of America Mathematical Olympiad (or USAMO), 42 points is a PERFECT SCORE.