Onboard a ship at an asteroid work site, four men tell each other tall tales to pass the time, and for something to do outside of their four hour work shifts. Hank starts in on a strange account of his trip to the planet Ganymedes, where he claims that the earrings wore the people there, not the other way around.
When he got to the planet, he said that crew had sent a group of three to meet the natives, who all wore a single fair sized hoop gold earring in one ear. They seemed fairly intelligent, with some knowledge of mathematics and philosophy, but primitive in other areas of life. They gave the linguist a gold earring as a sign of membership in the tribe, and the group went back to the ship. Over the next few days others from the crew went to visit the village, and more of them were given earrings.
Hank didn't think anything of it until one of the crew, Haynes, who had said he wanted to study the earrings but refused to let them put it on him (wanted it handed to him instead), had an incident. Hank was wandering the village when he heard a yelp, and ran back to find the natives standing around Haynes laying on the ground with a large red stain on his front. Haynes reassures him that he is fine and that the stain is just some spilled wine from the ceremony. He is wearing an earring.
Thinking this strange, Hank goes away and hides in a bush to spy, hoping to uncover something suspicious. He does. A native crossing the river has his legs bitten off by some underwater creature, and after very calmly speaking with his other friends, gives his earring to another native, drops dead, and is thrown in the river by the others. When Hank returns to the ship with his crew, he notices the stain is gone from Haynes' shirt, but there's a rip there, and a matching one on the back of his shirt, as if a spear had gone through him. He starts to suspect that the earrings have something strange about them—Haynes would be dead, but is walking in front of him, and the native hadn't seemed to notice he was dead until he handed the earring away.
Back on the ship Hank sees everyone acting strange, and pulls aside Dick, the only other crew member without an earring, to talk it over. Unfortunately it turns out Dick is in on it too, wearing a bracelet rather than an earring, and he and the others explain to Hank that they were in fact some kind of parasitic entities that had no self unless they were attached to a body—dormant until they could animate a human mind and body. They could run any body as long as it wasn't in too bad of shape—so though Haynes would fall flat dead if the earring was taken off, he was animated by the entity with it. Hank's parasite infected crew mates try to give him an earring too, but Hank escapes out the spaceship before they can put it on him. He never makes it, though—he can't think of anything to do, and so he just sits outside the ship until he passes out from lack of oxygen (the atmosphere is breathable only for a couple hours) and wakes up later inside the ship. At this point, the story is over and Hank's wide-eyed current crew mates stare at him for a few seconds before leaping for the gun Hank was cleaning during the story and making him strip down to ensure he isn't wearing any gold bracelets or earrings.
Hank does, goes to take a shower, and finds his crew mates relieved and embarrassed all at once, now sure he was just tricking them, telling a tall tale. The story ends with a telepathic report from Hank back to the Ganymedes people saying that he told the crew the true story of what happened and that their idea to embed themselves into the flesh of the people was a good idea, less conspicuous than the bracelets or earrings. He would take over the ship now, and they could go on to colonize Earth.