When Hannah Gruetn, the maid of Drew family, inherits a farm from a distant cousin, Nancy Drew and her father with Bess and George drive off for a scenic Oklahoma vacation. The plan is to sell off the property and pack up whatever momentos Hannah wants to keep. But a terrifying encounter with a tornado is just the beginning of the trouble.
In a duffel bag Nancy discovers what looks like a ransom note and a man named Jimmy Boyd appears insisting that the bag is his. Nancy suspects him as the kidnapper. She contacts the local police but they laughs it off as a prank. When charming Derek Owens, a tornado chaser at the local university, offers to help Nancy accepts faster than a lighting flash. But later he turns out to be the real villain and he tries to kill her by putting her in the midst of a terrible tornado. Nancy escapes and Derek gets killed in it.
Hannah gives the farm to Jimmy and he marries Mary, his lover. Drew family wished them a happy life and returned home.