An unmarked panel truck is flagged down by two men. One of the men force the driver to get out of the truck using a gun. The other man sneaks up behind the driver and slugs him with his gun.
As the robbers check out their loot, the driver awakens, jumps into their car and drives away to get help. The robbers discuss what they can do when a farmer hauling hay in a pickup truck drives up. One of the robbers grabs the flag and stops the truck, forcing the driver out with his gun. As the other crook piles the stolen paintings up, he then cuts up a painting worth $70,000, wipes his prints off the pry bar he used, and leaves it there to be found along with an envelope addressed to Mr. Carter Giles. The two crooks and the farmer get in the pickup truck and drive off.
The panel truck driver finds a gas station and calls the Highway Patrol to report the hijacking. Mathews arrives at the scene where Officer Dorsey is already investigating. Dorsey goes to run the hijackers' car as Mathews talks with the driver. The man tells the whole story again when Dan spots the hay on the ground. He calls for an all points bulletin for the two men and a hay truck.
At a gas station, one of the hijackers calls his boss to tell him the whole thing has gone sour. The boss man says he wants nothing to do with the paintings now and for the robber to get lost. But the robber says they are up to their necks in trouble and need help. Boss man says to take care of the hay truck driver and he'll handle the rest.
Mathews gets information from the DMV and sends Officer Dorsey to find a mug shot for the owner when a teletype comes in about a hay truck that has crashes with paintings still in it...and a dead driver. The chief and Dorsey take off for the location. Dorsey looks at the dead man and says it's murder. The coroner arrives and declares it was murder.
The deliveryman who was robbed identified the owner of the station-wagon from his mug shot. Officer Dorsey tells Mathews that the guy identified lives with his brother and they have a man staking out the place. Mathews reads the rap sheet and decides to "take an interest in art."
The two robbers ride with their employer, George Mills, to a safe house where he tells them to lie low for a while, stay indoors and forget about the paintings. The killers say no deal, they will not forget Mills or anything to do with the job until they are paid. Eddie threatens violence but Tony calms him down.
Chief Mathews interviews Carter Giles, the man whom the paintings were on their way to. Dan comes up with a plan to trap the thieves and wants a list of all of Giles associates.
Giles calls Mills and sets the trap, telling him that the cops have no leads and he's going to need a half a mill for ransom. Mills is puzzled because he's not asked for any ransom. He goes to see Giles who is still speaking with Dan and wants to know what is going on. Mathews asks about the arrangements for the paints to be shipped in and Mills tells him everything. Dan then asks Giles about the ransom and he says he has to pay it, which is not true. Mills questions paying the ransom and Giles plays the jealous lover who wants the paintings back no matter what the cost. Mills asks Mathews to step in but Dan says there's nothing he can do to stop Giles and leaves. Giles tells Mills to have the money there in the morning.
At headquarters, all the background arrangements for the shipment were being investigated. The information that came back was that everything was handled correctly, confidentially and securely. Only Carter Giles had each bit of information. But Giles said he didn't even know a truck was involved. So Mathews suspects something and orders Dorsey to get a court order for phone records of Giles and all his employees. The phone records came in the next morning and showed that Mills was the one who called and received the information about shipping, not Giles. Mathews orders him brought in.
Mills calls the two killers and tells them he'll see them soon with the money. They say the longer it takes, the more it will cost. Mills leaves his house just as Mathews and Dorsey arrive so they decide to tail him. He takes the officers right to the hide-out of Tony and Eddie who are going nuts waiting. Mills walks in with a case and the two crooks expect to get paid. But Mills pulls a gun on the two men saying that he's going to turn them into the police if they don't give up the paintings. Just then the door bell buzzes distracting Mills and the two crooks jump him, grabbing the gun. But Dan and Dorsey kick in the door and apprehend the three men. Mills tries to defend himself but Mathews knows better and the two officers take the three men into custody for the robbery of the paintings and the murder of an innocent man.