巨型蜘蛛入侵美国小镇，无辜镇民如何逃脱升天？

Trapped in a maze of endless desert highways, bound by a vital deadline, and pursued by an unseen menace....Jeremy Stanton is about to take the longest ride of his life. He will learn that when you reach the crossroads of life...you must be careful which way you turn.

A scientist develops a formula which will cause animals to regress to the form of their primitive ancestors, and tries it on himself with disastrous results.