With Earth overcrowded by its own population, humanity must look to the stars to survive. Advance crews of terraformers prepared alien worlds in advance of the colonists to come.

When those terraforming crews introduced the alien Quill to worlds where they did not belong, they saw them only as a mindless form of fungal life. But the Quill multiplied and mutated until they were no longer harmless, making the planets impossible for humans to inhabit. People expecting their new homes were crowded into space stations waiting for a solution to be found. In the ensuing chaos, many stations were lost.

For the survivors, their only hope rests in finding a way to wipe out the Quill before the final stations fail.