The Protege — Charlotte Armstrong

What, was a respectable old widow like Mrs. Moffat doing with that bearded young stranger in her house?

He told her he was Simon Warren, that he had lived next door when he was a child and had been friends with her grandson -- who had vanished mysteriously seven years before. So she invited him for lunch. He stayed for months.

Mrs. Moffat asked few questions, although she suspected that he was not "Simon Warren" at all. But she was still convinced that her "protege" was just a troubled young boy when her granddaughter Zan arrived.

Then both women watched with dawning horror as a bizarre scheme unfolded a scheme to revive the past terror they thought they could forget . . .