Gil Ryan, a shady underworld figure, is the star witness in the criminal trial of Lucas Hume, a man with connections to city politics. Then Ryan is gunned down in spite of his police protection, and Hume is found standing over the body, holding the gun that fired the shots. Despite what appears to be an open-and-shut murder case, however, Joe Mannix is hired by Hume's sister, who claims to have had an affair with Ryan -- and wants Mannix to prove that she, not her brother, was the one who shot Ryan.
—aldanoli