In celebration of her forthcoming wedding, a bride-to-be embarks on her hen night at Whitby Funfair, where a clairvoyant gives her information linked to the death of her father, who went missing in action in the 1940s, prompting her to postpone the wedding until his body has been found. When she is found injured on the moors a few days later, Merton and the team investigate and find themselves incurring the wrath of the Ministry of Defence. Meanwhile, a bogus police officer begins causing havoc in Ashfordly. As Mike tries to lure the imposter into a trap, he is left with a dilemma when the troublemaker catches Bellamy filling in for Gina after hours at the pub.

The residents of Aidensfield are terrorised by a ruthless marksman with a sniper, who begins his reign of terror by murdering Liz's ex-boyfriend, a newly arrived doctor she dumped after he refused to tell his wife about their affair. While she attempts to comfort the victim's bereaved spouse, Bellamy is the next target, but luckily escapes with a flesh wound. Merton and DI Shiner fear the target is the police force itself when they discover the assailant is using an Army-issue weapon. As the team race to prevent another innocent killing, Mike receives a life-changing job offer that will shape his career in the force. Meanwhile, a newcomer in a Bentley limousine makes a big impression on Gina and David for two very different reasons.