Wrongly convicted after a mysterious accident, Edmund Amesbury, the heir of a prominent San Francisco family, makes an escape to prove his innocence. He soon discovers that the conspiracy against him involves a long sought-after painting that might prove his lineage to France's last king. Betrayed and abandoned by his family and friends, and with the police on his heels, Edmund finds an unlikely ally in a shadowy cat burglar who introduces him to the underworld of forgers and stolen-art dealers.