The Florida Keys - two astronauts, on pass, marlin fishing. Eight days before the launching of the United States' first moon shot.
Two astronauts I'll be calling Gilligan and Skipper are working on their disabled boat as two guys begin flying their helicopter over it. The pilot nods to his companion and a smoky red gas is dropped from the copter onto the boat, as a beachcomber observes from the beach.
Gilligan looks out the window obscured by red haze and complains about the fog, while the Skipper calls for a mechanic, saying he doesn't want to get caught in the fog. For some unknown reason, Gilligan decides to open the window and allow the red fog in while making crazy faces in its fiery glow, while the person the Skipper is in contact with over the radio says there's been no fog reported.
He sees his shipmate contorting and goes over to find out what's up and begins contorting himself. He drags himself back to the radio and communicates that it's not fog, it's red, and he can't breathe. He passes out as the voice on the radio repeatedly calls for Major Banks.
Starring Roy Thinnes as Architect David Vincent