By Hal Clement
A Nomadic kin sooner or later is allied with an octopus-like alien who can live to tell the tale in earth's new surroundings, which has mixed with nitrogen. people needs to stay in shelters with oxygen-generating vegetation, or use appropriate respiring gear. a few of earth's unique existence kinds have mutated to outlive within the replaced surroundings. considering virtually no metals can exist within the corrosive surroundings, any expertise is predicated on ceramics or glass.
Some people are suspicious of the extraterrestrial beings, blaming them for the switch within the surroundings for the reason that they're tailored to it. The family members has a virtually deadly come across with a bunch of such humans, who're preserving one other alien hostage. but the extraterrestrial beings may be able to pool stories biochemically in order that they develop into an identical character in our bodies. Their mixed wisdom and talents aid the kin to flee. the adventure finds simply who the extraterrestrial beings are, the place they got here from, and why the earth's surroundings changed.