Highways in Hiding concerns ESP and a disease that turns men into stones or supermen. This is set against the plot of a secret society that is harboring people that are infected with a space-borne illness called Mekstrom's Disease. People get infected and it slowly turns them into a sort of rock. The hardening begins at one of the extremities such as a finger or toe and slowly begins to creep up the infected limb. Eventually all the extremities are hardening and the disease makes its way to the body proper. At this point, the body is hardened until the vitals fail and the patient dies. A secret society has found a cure for the infected, but, in order to hide themselves from the public at large they have devised a hidden highway program that leads the infected to "Mekstrom safe-houses" of sorts.