Robbery detail. A pair of aarmed robbers hold up a restaurant. One gets away, but the other is shot.

Frank Smith joins Joe Friday on the smoggy day as they catch up on visiting relatives, and the details of the robbery. What’s the condition of the injured criminal? Phone calls are made, and interviews are begun. Crooks are rounded up. The restaurant owners are questioned, looking for any remote detaiil to link the missing robber to the crime. A tall man with a loud voice, ordering folks around. Maybe the worst part for the victims is the theft of a signet ring, a family heirloom.

Mug shots are left with Mr. and Mrs. Reiner, and the investigation continues. Informants may be of help, but the cops deliver more mug shots to the victims. Though they remark over the looks of the criminal faces, none of them seem to be their robber.

The promising case ends with Joe and Frank feeling further from a solution. When the diamond signet ring shows up in the sale of a car, the case takes on new traction. Joe connects with Las Vegas police to close in on their man.

A known associate claims to not be involved, and going sstraight. Joe believes him. Will the old felon help set up the robber on the run?