Maxine Cooper

A doomed female hitchhiker pulls Mike Hammer into a deadly whirlpool of intrigue, revolving around a mysterious "great whatsit." (imdb)

Milly, a lonely older woman, marries Burt Hanson, a much younger man. But after the wedding, Milly discovers that Burt has been mentally unhinged by the discovery, some time before, of his first wife Virginia in the arms of his father. The reappearance of his father and former wife in Burt's new life throws him into deep mental distress, and Milly must decide whether to have him committed to a mental institution. (imdb)