The plot, old-hat though it is, does provide an opportunity for that wonderfully seedy villain, David Dirby, to do his dirty work and more importantly, to tie all the thrillingly on-the-spot railroad footage together. Railroad buffs will enjoy all the atmospheric detail director Johnson has obtained by filming in real freight yards and inside and alongside real steam engines and rolling stock.

Diamond thieves have infiltrated the staff of O'Day Jewelry. The Los Angeles Police Dept. employs their newest weapon, an airplane, to help smash the diamond theft ring.