In the second episode, the detectives begin an investigation into an armed robbery at a post office in which thieves seized £186,000.
The cashier tells police he was knocked out with chloroform by a raider, who is shown on CCTV wielding a gun before emptying the safe and escaping in the cashier's car. Something about the CCTV footage tells detectives all is not as it appears - the robber seems to deliberately place the gun in view, and the cashier seems prepared for him to attack.
