Noah Benton, a teenager with a great memory, a head for arithmetic, and dreams of excitement, is hired along with his older brother to help drive a herd of Texas longhorns to Abilene, Kansas. But Noah’s trail boss happens to be John Wesley Hardin, a notorious killer who thinks Texas lawmen won’t look for a fugitive in a crew of hard-working cowboys. After Hardin sees a profit in Noah’s ability to count and memorize cards in gambling dens, Noah’s dreams of excitement quickly turn into nightmares — for Hardin will kill with little provocation.