Nell Pratt, president of the Pennsylvania Antiquarian Society in Philadelphia, gets involved in an explosive mystery when an arsonist sets a series of warehouse fires that results in the death of a guard--and involves the Fireman's Museum's most prized possession.

When the entire collection of the Fireman's Museum ironically goes up in flames, Nell Pratt discovers one of the charred pictures isn't the one that was originally exhibited. But getting to the bottom of the mystery is bound to get Nell burned...