The story is set at the height of the Red scare in 1957, when Marshall College's Professor Jones runs afoul of the FBI and has his patriotism questioned. The Colonel Professor and a crack team of Russians manage to force their way into a secret U.S. Army base in Nevada. They bring the kidnapped Jones with them and force him at gunpoint to help them find some mummified remains from a plane crash.
The mummified remains have a connection to the crystal skull of the title, and both deeply interest Spalko, who feels that if she can find where the skull came from, great knowledge will be hers.
The film's final section plays out deep in a South American jungle, with everyone hell-bent for the secret of the crystal skull. It offers lots of animal action as well as great stunts both CGI and physical. "Crystal Skull," the fourth Indiana Jones film and the first in 19 years, proves to be one of the better ones of the series.