Wealthy widow Helen Mercer hires a young woman, Gretchen Addison, to act as her personal assistant and companion. Unfortunately, Helen is a poor judge of character, as Gretchen is part of a murderous extortionist duo with her boyfriend, Jay. However, Gretchen has second thoughts when she develops genuine affection for Helen. When Gretchen informs Jay that she wants to call off their plot, he refuses and carries on with the plan. Now both Helen and Gretchen may be in grave danger.
In the early hours of the night, young David Maclean sees a flying saucer land and disappear into the sand dunes just beyond his house. Slowly, all of the adults, including his once loving parents, begin to act strangely.
