Newly recruited to the renowned Pinkerton Detective Agency, Finn Dexter is on leave visiting his father's ranch near Ellsworth, Kansas, when a letter received from a friend causes some concern. Ned Sullivan's son Matt has been shot and he has asked if the boy can stay on the ranch. When Matt arrives by train the next day, a hired gunman tries to finish the job begun in Kansas City but fails for the second time. Finn goes after the killer and realizes that there is much more to this shooting than meets the eye. He heads for the city and uncovers a nest of vipers operating illegal rackets from the Snake Eyes casino, operated by Lew Faringo. Finn must call on all his newly acquired detection skills if he is to outwit the gang and bring the real criminal mastermind to justice.