Invasion

Cassy Winthrope notices something wrong with her boyfriend Beau after he comes down with what looks like a short bout of flu. Beau has always been the careful, predictable type who never misses a class and can't stand big dogs. Now he is stronger, quicker and sharper than before, he skips lectures, and he is strolling around town with a bullmastiff at his side.

When Cassy tells their friend Pitt what she has seen, the two begin to realize that Beau is not the only one. Nearly everyone in their small college town seems to have caught the same illness and shown the same odd changes. Small black disks have also started turning up in places they shouldn't be, and anyone who picks one up gets stung. Cassy and Pitt start to wonder whether the disks and the spreading sickness are linked.

No doctor can put a name to the illness, and the people who aren't infected are running out. Cassy gathers allies from the community and from the medical world, choosing only those who have not been exposed. Every day the changes sink deeper into the people she loves, and she has to work out what is happening and how to stop it before it can no longer be undone.

Robin Cook, the author known for his medical thrillers, pushes the genre toward science fiction here. The story asks what we really understand about the human body and the universe around it.