FRYEAN MYTHOS: *drama*
CAMPBELLIAN FUNCTION: *cosmological, sociological*
The Enterprises answers a distress call from an uninhabited planet, and as they near the world they find evidence of a destroyed ship. Kirk beams down with a landing-party and meets the former inhabitants of the ship, the Kelvans. These aliens, natives from the Andromeda Galaxy, have assumed humanoid forms-- their original natures are never disclosed-- because they've decided, rather quickly IMO, that they must do so in order to take over the Enterprise. Rojan, leader of the small party of aliens, informs Kirk that a cataclysm caused them to leave their galaxy, though it was a generation-ship-- meaning that Rojan and all of his male and female aides were born on the ship. It's their duty and perceived destiny to scout out new homes for the Kelvans, and to do so, they'll use the Enterprise for the same purpose, Rojan admits that he himself will never see whatever home they colonize; it will only be one of his descendants. Nothing is said about whether the Federation citizens will be allowed to breed during the trip, but either way, Kirk and his crew seem fated to die on the ship.
The Kelvans' methods of conquering the ship are impressively simple: they can paralyze human beings with the devices on their belts, and, to get the majority of the crew out of the way, they can also reduce individuals down into dodecahedron cubes. Soon the ship is on its way to its new destination, and only four crewpersons-- Kirk, Spock, McCoy and Scott-- are allowed to remain in their normal forms, to monitor the ship's performance.
After a failed attempt to foil the aliens by destroying the ships, the crewmen hit upon a way to use the Kelvans' mimicry of humans against the, The Fontana-Bixby script picks up on a common SF-idea, tossed off in "Catspaw" but used to much greater effect here-- that aliens who mimic humans may be seduced into acting like humans. Hence, the Shakespeare-derived title: the Kelvans are "roses" who go by another name, but by taking on the semblance of humanity, they will learn how "sweet" it is to experience the gamut of human emotions. (This is, if one were keeping score, another story in which the multifaceted nature of the emotions takes precedence over the logical faculties.)
The most interesting sociological facet of the narrative is that in many ways the Kelvans are a mirror-image of Starfleet in its more unbending moments, though the Kelvans are also devoted to conquest and are initially indifferent to the sentiments of the conquered. They're also pure incarnations of the Protestant ethic of "deferred gratification," and Kirk defeats them in part by pointing out that they will be aliens and enemies to normal Kelvans by virtue of having "gone native." Thus, Kirk argues, they might as well forget about scouting new worlds of conquest for their people and settle down to enjoying their new existence-- which is pretty the obverse of the moral of "The Man Trap."