Armed robbers are targeting post offices around Aidensfield, leading to Mason working with his old flame Rachel Dawson. Her career meanwhile is in doubt, following being in an affair with a senior colleague. Carol isn't overly impressed when she spots Joe in a romantic clinch with Rachel, who denies this and says it was in the line of duty and nothing guilty. Meanwhile, Peggy offers to house clean for a man. Oscar thinks she is after the man's money. However, it is the man's wife, who is a resident in a nursing home, who has a shady past.
