A widowed woman is being stalked by her husband's murderers.
A routine investigation of a shocking murder takes a bizarre twist when the killer contacts the reporter and appoints him his personal spokesman. As the killer's calls and clues increase, the reporter is lured into a deadly trap.
Two scientists involved in chimpanzee research -- one maintaining that the animals should be kept in their native habitat in Africa without human interference, the other trying to train them in sign language in a domesticated atmosphere -- join forces when they learn that the government plans to cut off the language grant and use the chimps for radiation research.
A retired businessman notices that there has been a rash of ships and planes disappearing off the Florida coast, and he starts to investigate.
A ride to the airport unites three women whose husbands are either prisoners or missing in Vietnam.
A scientist and his team of underwater explorers search for the culprit who has stolen the world's supply of nerve gas and hidden it somewhere in the ocean.
The Hollander family's European vacation is interrupted when their plane is forced to land in Vulgaria. The Hollanders leave the plane to take pictures which results in accusations of spying. Chased by Vulgarian soldiers, they take refuge in the American Embassy under the protection of the absent ambassador's hapless son.