Two years have passed since Jack Argyle, convicted of murdering his mother, died in prison—died bearing the stigma of the most heinous crime imaginable. And no one listened to his protestations of innocence. But suddenly the situation changes—polar explorer Dr. Calgary returns from an Antarctic expedition. He knows for certain that Jack had an alibi and is determined to find the real culprit and exonerate the convicted man, even if posthumously. Argyle's family is unhappy with this turn of events: now it turns out that the killer is one of their own, perfectly respectable citizens...