Reporter John Strasheim, Captain Wallich, bioanalyst Renata Baucum, and rest of the small crew of the space ship Louis Pasteur travel on a dangerous mission from Jupiter's moon of Ganymede and the Immunity.  They visit the Gladholders in the asteroid belt, then travel to the inner solar system, including Earth, which has been taken over by the feared Mycosystem.

I was quite surprised and impressed at how skillfully McCarthy handled this story.  He succeeds where, to my mind, better-known authors like Bear and Benford often fail: He presents a mind-blowingly bizarre future in a hard SF setting without leaving the reader feeling too detached and disinterested.  The characters don't have a great deal of depth, but they're quirky enough to make for enjoyable reading.  I particularly enjoyed Wallich's tickler mechanism, which is intended to help him interact with others, but mostly just causes him to laugh at inappropriate times.  McCarthy manages to make his post-apocalyptic future nearly inconceivable yet quite believable at the same time.  (The only lapse in plausibility is expecting us to believe that Strasheim's idea that saves the day at the end never occurred to anyone else before.)  Better yet, McCarthy uses the Immunity's retreat into paranoia to communicate interesting thoughts about our unfortunate human tendencies.