Jake Malloy is a fledgling private eye in post-WWII San Francisco. When a murder occurs, during what appears to be a botched robbery, Jake sets out to find a Bonnie-and-Clyde-type young couple responsible for similar robberies. A bloody note found at the scene of the crime is believed to have been written by the victim as he bled to death. What was the dying man trying to say? The bloodstains on the note make it hard to decipher but it appears to indicate a mystery woman is involved.

As Jake investigates, new leads and new mysteries develop. When the full meaning of the note is discovered, it reveals hidden motives and crimes.