Texas City: Johnny Mack Brown substitutes brains for brawn during most of Texas City. Cast once more as a U.S. marshal, Johnny investigates when several government gold shipments are hijacked. Someone has been tipping of the outlaws as to when and where the supposedly secret shipments will take place. The principal suspect is dishonorably discharged cavalry officer Kirby (James Ellison), but Johnny has a gut feeling that Kirby is innocent on all counts.