Francesca Crawford is sleeping when the murderer enters her apartment. The door is locked, but the killer is agile, climbing down from the roof, knife in hand. The killer is expert, stabbing Francesca only once, straight through the heart. She doesn't even wake up.

John Andera comes to Dan Fortune, the one-armed private investigator, begging him to find justice for Francesca. Andera is a salesman, an ordinary fellow who met the girl - who turns out to be the high-class daughter of an upstate mayor - a few weeks before her death. He was instantly infatuated, so he offers Fortune $2,000 to find the man who killed his young love. But to understand her death, Fortune must learn who she was in life, and this girl will prove one of the most perplexing mysteries he has ever faced.