Things begin with the shirtless mineralogist Paul Carlson digging out in the New Mexico desert. ("Ah, a rare sliver of concrete from the Eisenhower Epoch.") Following an over-explained prank attempted on him, he meets up with the Native American professor Johnny Longbow and the photographer Kathy Nolan, and as Johnny Longbow describes with a faint air of world-weariness the ingredients of his famous stew (which became a running gag in some late-period MSTings) we learn there's going to be a meteor shower of genuine moon rocks. Paul and Kathy set out into the night to observe, but it just so happens Paul gets zapped by a fragment...
Even going to a seventies folk rock performance doesn't help Paul's sudden ill spells, and he gets left at home by Johnny Longbow and Kathy. ("No care is the best care.") Then, as Paul keeps getting sweaty and removing his shirt ("He's got a severe allergy to shirts." "Drink me in, world--I'm freshly oiled and ready to rock!") random locals start getting horribly killed... The police enlist Johnny Longbow's help, and he provides a slide show of a Native American legend even as we discover the meteor fragment is now embedded in Paul's brain.
Expert help is called in only to discover the fragment has multiplied and sooner or later Paul, transforming into a murderous and peculiar-headed green creature ("I'm ready to fight Captain Kirk!") at night, is going to spontaneously combust. For some reason, he doesn't take this well, and escapes intending to do himself in. None of his schemes seem to work, though, and at last he's transformed and threatening Kathy when Johnny Longbow shoots him with an authentic Native American bow and arrow tipped with a moon-rock arrowhead. This accelerates the spontaneous combustion process, and everyone departs into the night in that specially bleak 1970s fashion.
As I've often concluded of late, this episode did seem to start off slowly but picked up as it went along. The "host segments" featured yet another attempt by Mike to escape, this time using a universal remote to control Professor Bobo, whose brain has just been exposed and wired by Pearl Forrester, Mike providing narration for the complete and authentic history of the seventies folk rock band, and Crow and Tom Servo attempting to discover just what kind of pyjamas Mike wears.