Blaketon becomes the prime suspect in a murder enquiry when he is asked to spy on an adulterous coal merchant by his wife. After the man is found dead, his wife claims she and Blaketon are lovers, leaving Rob to lead his own investigation to clear the private detective's name. Meanwhile, Bellamy falls in love with a young widow with three children, living on the Ashfordly council estate, when he attends to a burglary at her house, and Peggy fails to back a winner when she buys a greyhound that refuses to run.

Lord Ashfordly and his staff go away for Christmas, leaving Ashfordly Hall in the hands of his lordship's old army pal after rumours of a planned robbery emerge. However, he soon arouses Rob's suspicion when he harbours a young tearaway and tries to teach him a valuable life lesson in a violent way when the thief repays his act of kindness by stealing Lord Ashfordly's valuables. Meanwhile, Blaketon and Peggy go into competition when they both open Santa's grottos at the pub and Bernie's garage, whilst Ventress' nose is put out of joint when his wife falls ill and Gina, Helen, David and Bellamy to draw straws on who gets to invite him for Christmas dinner.