***SPOILERS*** M Squad Let. Det. Ballinger, Lee Marvin, goes undercover as a working stiff from the docks to catch cop killer Rex Lane,Lee Farr, who's gone so far as murdering some eight people six of them policemen from as far as the state of "Big SkY' Montana to the "Windy" city of Chicago. Using the Chicago sanitation department to track down a three year old "New Feature" magazine in the garbage that Lane disposed Ballinger and his M Squad zero in on the on the lamb Lane who's shacked up with his girlfriend Olga Patucek, Gail Kobe, in a Chicago slum.
Caseing out the place before making a raid on it Let. Det. Ballinger plans to avoid bloodshed and take the "You'll never take me alive" Lane alive to prevent him from impressing his many youthful follower who look up to the murderous creep as another John Dillinger or Jesse James. This strategy on Ballinger's part is to keep the number of people, including Lane's girlfriend Olga, from getting shot and killed to a minimum which Lane in wanting to go down in flames wants the exact opposite to happen.
***SPOILERS*** Catchiung Lane flat footed in him trying to escape his fate, on of all things a ironing board, Ballinger and his partner Det. Ben Cooper, Russ Conway, end up disarming Lane and having it out with him as Ballinger bruised and bloodied finally puts the cuffs on the cop killer. Refusing to get medical help Ballinger in the end only wants only to go to the nearest bar and being off duty get himself good and juiced and forget, in what he just went through, the whole adventure.