Michael and KITT must guard a mysterious and volatile new isotope, "Cernium," inadvertently created in a Foundation laboratory. Feared international terrorist Phillip Nordstrom (John Considine, who'd previously guest-starred in "Knight in Disgrace") plans to steal the isotope during its transportation and layover in Chicago. He intercepts Michael with "The Juggernaut," a specially designed mobile battering ram that smashes into KITT and destroys the trusty Trans Am. Separated from the Knight Foundation, Michael enlists some new friends to re-build a better KITT and retrieve the missing isotope. The guest cast includes Blair Underwood (L.A. Law) and indie-cinema star Mary Woronov (Eating Raoul).