Strange aliens land in the Midwest, taking over people's minds in order to spread their dominion. Sam Nivens and Andrew Nivens, aided by Mary Sefton, are part of a government agency who must stop the the aliens before the aliens get to them... 来自外太空的奇特生物悄然入侵一个小镇，寄生在人类脊椎上，侵入大脑，使人丧失自主意志，成为它们的傀儡，帮助它们迅速扩散繁衍。探员Andrew、Sam与外星生物学家Mary联手消灭这些入侵者。
