Another without Christie's trademark detectives, but still definitely worth reading. The premise is a bit thin. A scientist was so isolated, in Antarctica, and with a case of "partial amnesia," that he didn't know he could provide an airtight alibi for a convicted murderer, who has since died in prison, until his return. Yet Christie makes the most of this premise. Her Dr. Calgary believes Jacko's family will be so relieved to learn that he's innocent, that he doesn't realize that the question will again be raised of who, then, did commit the murder. The playing out of that question is a fascinating psychological story, especially as Dr. Calgary believes it's his responsibility to help solve the puzzle.