The successful TV and movie actor who played the role of FBI agent Robert Graham in the 1954 nuclear giant ants movie "Them" was James Arness. Special Agent Graham was assigned by the FBI to the state of New Mexico to investigate a situation where something very odd happened to FBI Special Agent Ellinson and his family. The family was on vacation with the agent (his wife, son, and daughter). The little girl is found; the other members of the girl's family remain missing.

Agent Graham and the inhabitants of a small Southwestern town near Alamogordo are forced to face the awful fallout of what happens when radiation from bomb tests creates giant, mutant ants. These ants decide to descend upon the local community. Facing human extermination, a team of scientists along with Graham strive to figure out how to stop "them".

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