An opening sequence features Frank Bigelow walking through the long hallway of a police station to report his own murder.
From here to the end, the story is told in flashback.
Bigelow is a hard-driving accountant and notary public in Banning, California, who decides to escape for a fun vacation in San Francisco.
At the hotel, he is invited to join a group of conventioneers for a night out.
He ends up at a nightclub where, unnoticed, a stranger swaps his drink for another one.
The next morning, he feels extremely ill.
Doctors determine that he swallowed a poison, "luminous toxin," for which there is no antidote.
