The Bluestone 42 team go out on routine operations with their CIA liaison officer Carter, where things take a drastic turn. Back at the base, they are introduced to Mary, the new padre, who Nick takes an instant shine to.

Nick tries to find something tastier to eat and is intrigued to hear about a local delicacy - the Afghan Tiger Gecko. Mary encourages Nick to let Millsy run a re-training exercise.

Mac and Rocket are upset after a football game between Hibernian and Celtic is interrupted with news of an impending bomb factory raid. The team rescues a Danish Aid Worker called Astrid who has been taken hostage by the Taliban during the raid. Astrid develops a crush on Nick. Simon has written a memoir called, A Foot In Death’s Door, much to everybody's amusement.

Bird and Millsy realise how much Nick suffers from been superstitious when he runs out of his favourite sweet - Fisherman's Friends. Mac and Rocket convince Simon to take place in a game of Ultimate Fencing Deluxe.

Nick tries to prove to the padre that he is not superstitious. Simon tries to earn respect by joining in dangerous homemade games with Mac and Rocket.

Nick and Simon help each other to learn to dance, whilst the arrival of vet Parikh reveals Bird as a terrible flirt.

The dangers of active duty in Afghanistan come close to home for the soldiers after a mortar attack on their patrol base sends them diving for cover.

Nick has to deal with a gruelling challenge with a booby-trapped car bom. Simon attempts to stand up to his fiancee.

It's Christmas Eve and the team are joined by Corporal Gordon House as he begins his tour of duty. Captain Nick Medhursthas to try and get him up to speed, but as Towerblock finished top of his class on the High Threat Course, he believes that he knows everything. He soon discovers though that things are different in the field, even on Christmas Day.