It is Weinbaum's third story featuring Hamilton Hammond and Patricia Burlingame, a sequel to "Parasite Planet" and "The Lotus Eaters".

In Weinbaum's version of the Solar System, all of the gas giants generate significant amounts of infrared radiation, enough to produce Earthlike environments on the inner moons of Jupiter and Saturn and on the surface of Uranus itself.

The surface is shrouded in a thick fog which absorbs radio waves as well as visible light, and there is no planetary magnetic field to work a compass, so the members of the expedition, including Hammond's wife, the Venusian-born biologist Patricia Burlingame, must remain tethered to the ship to avoid getting lost.

When they receive a signal from the ship, they hurry back to find it under attack by an immensely long black creature made up of dozens of connected segments.

Back on board the Gaea, Burlingame reveals that shortly after leaving her tether, she ran into a segment-creature which began chasing her.