Hercule Poirot thought to himself as he turned out the light by his bed: "I should know that voice again…"

Their elbows on the windowsill, their heads close together, Raymond and Carol Boynton gazed out into the blue depths of the night. Nervously, Raymond repeated his former words: "You do see, don't you, that she's got to be killed?"

Carol Boynton stirred slightly. She said, her voice deep and hoarse: "It's horrible…"

"It's not more horrible than this!"

"I suppose not…"

Raymond said violently: "It can't go on like this-it can't… We must do something… And there isn't anything else we can do…" Carol said-but her voice was unconvincing and she knew it: "If we could get away somehow…?"

"We can't." His voice was empty and hopeless. "Carol, you know we can't…"

The girl shivered.

"I know Ray- I know."

He gave a sudden short bitter laugh. "People would say we were crazy-not to be able just to walk out-"

Carol said slowly: "Perhaps we are crazy!"

"I daresay. Yes, I daresay we are. Anyway we soon shall be… I suppose some people would say we are already. Here we are calmly planning, in cold blood, to kill our own mother!"

Carol said sharply: "She isn't our own mother!"

"No, that's true."

There was a pause and then Raymond said, his voice now quietly matter-of-fact: "You do agree, Carol?"

Carol answered steadily: "I think she ought to die-yes…" Then she broke out suddenly: "She's mad… I'm quite sure she's mad… She-she couldn't torture us like she does if she were sane. For years we've been saying: 'This can't go on!' And it has gone on! We've said, 'She'll die sometime'-but she hasn't died! I don't think she ever will die unless-"

Raymond said steadily: "Unless we kill her…"

"Yes."

She clenched her hands on the windowsill in front of her.