Alien parasites plan the conquest of Earth by attaching themselves to the spinal columns of men in power. They recruit disaffected loners to spread their infection... unaware that one of the loners is a government agent sent to infiltrate them.

Four scientists have disappeared, and the Space Security Agency discovers that they all were born in a small town in Spider Country and are extraordinary physical and mental speciments... and a fifth man meeting the same criteria is still there and being held on a murder charge.