In Los Angeles, hard-nosed police lieutenant Jim Cordell and his partner, Lt. Phillips, respond to a robbery call at Wrigley Field. When they arrive at the baseball park, they discover that the call was a false alarm and head to the station. The caller, crook Dave Purvus, who has been clocking the police's response time, then meets with acquaintance Benny McBride to discuss a heist. Anxious to secure some money for his estranged wife, greedy burlesque queen Yvonne LeDoux, Benny agrees to participate, unaware that the self-possessed and cautious Purvus is having an affair with Yvonne. As agreed, Benny brings in two other veteran criminals, Al Mapes and William "Ace" Foster, to the plot, which involves the robbery of an armored truck at Wrigley Field. On the day of the robbery, Foster pretends to be fixing a jalopy next to the parked armored truck and, on Purvus' cue, causes the car to backfire and blow black smoke at the truck's guards. After the crooks overwhelm the surprised guards and break into the truck, Benny notifies the police. Unknown to Benny, Jim and Phillips are driving in the area and respond to the call much faster than Purvus anticipated. Jim and Phillips exchange gunfire with the robbers, who shoot Phillips and escape in their getaway car. Later, at the hospital, Jim learns that Phillips, his longtime friend, has died from his wounds and that rookie detective Danny Ryan is going to be his new partner. Aware that the crooks have changed cars and that one of them is wounded, a determined Jim orders roadblocks put up around the city. Although the robbers manage to pass through a roadblock near the harbor, the police soon discover their oversight and radio in the car's description and general whereabouts. At his dockside hideout, Purvus shoots and kills the wounded Benny when he demands his cut and insists on going to a doctor. Foster then dumps Benny's body and the car in the harbor, but before the car becomes completely submerged, a passing patrol car sees it. Having narrowed the crooks' location, Jim and Ryan comb the docks and catch Foster as he is making his way to a motorboat. The police kill Foster, but are unable to stop Mapes, who is already in the boat, and Purvus, who is still on the dock. Later, Jim and Ryan go to Benny's apartment and there find a photograph of Yvonne as well as Purvus' telephone number. Before they can arrest Purvus, however, he sneaks out of his apartment and flees. After a forensics expert identifies the lipstick on one of Purvus' shirts as being a theatrical type, the detectives go to the theater where Yvonne works. There they spot Mapes, who had come looking for his cut, and arrest him. After Mapes reveals Purvus' connection to Yvonne, the detectives put a tail on the dancer and plant a listening device in her dressing room. When Yvonne suddenly quits her job, Ryan offers to impersonate Mapes, whom she has never seen, in the hope that she will lead him to Purvus before they both flee the country. Purvus soon discovers Ryan's impersonation, however, and lures him into Yvonne's car, where he holds him at gunpoint. Unknown to Purvus, Yvonne's car is also wired with a listening device, and as she drives, Ryan mentions street names for Jim's benefit. Sensing that Ryan is up to something, Purvus orders Yvonne to stop and shoots the detective. Before passing out, Ryan lets Jim know that Purvus and Yvonne are headed for the airport, where they have chartered a private plane. The police notify the airport, and Purvus and Yvonne's plane is stopped on the runway. Purvus tries to shoot his way out, but is shot and then crushed to death by a landing plane. Later, Jim visits a recuperating Ryan at the hospital and proudly shows him a detective magazine article about the case, in which their names are prominently mentioned.