Filmed in France by the Primagraf company, Flames of Justice was designed as a vehicle for European stage favorite Julia De Kelety. According to some reports, De Kelety also wrote the picture, and may well have directed it. The heroine, Marie (De Kelety), is in love with Conrad, the son of her landlord. Conrad's father breaks up the romance, whereupon the boy runs off to parts unknown and the girl accepts a job as maid in the household of Judge White. When the judge's son steals the family jewels to pay his gambling debts, Marie is immediately accused of the crime -- and when Conrad pays her a surprise visit, he is fingered as Marie's accomplice. The despicable son tells Marie that he will persuade the judge to free Conrad, if only Marie will become the son's mistress. Marie agrees, but the son reneges on his promise and Conrad is sentenced to life imprisonment. Bearing the son's child, Marie leaves the judge's household in disgrace and tries to kill herself. But a curious last-reel plot twist enables Marie and Conrad to enjoy a happy ending, while simultaneously condemning the villainous son to a grisly demise.