In The Hat Box Mystery, a private eye is called away on business. While he's gone, his secretary, Susan, takes an assignment from a man who wants evidence of his wife's infidelity. He gives her a hatbox that he's rigged with a camera (actually a gun) inside, and Susan unwittingly shoots the woman. In Hollywood Mystery, fists and bullets fly when a scheme hatched by cocky Dan Ryan, a fast-talking Hollywood PR man, runs afoul of the mob.