Platoon: Life In The Barracks | Preview (5)

In episode one, the thirty soldiers of 13 Platoon, D Company, 5th Battalion The Rifles come together for the first time. They come from all different walks of life and corners of the country, most with little experience beyond basic training.

Their challenge is to become a fighting unit, capable of deploying to Eastern Europe in six months' time. At the helm is 22-year-old Platoon Commander Lieutenant Tom Drew, fresh out of the Royal Military Academy Sandhurst and Infantry Battle School, but with just four weeks experience of life in camp.

Together with Platoon Serjeant Dan Mann, he's overall responsible for the success or failure of the platoon. With the clock ticking, he throws them in at the deep end with a week-long exercise in the Brecon Beacon mountains.

Here, the Riflemen undergo 'Top Dog', a competition scrutinising their fitness and mental resilience. Over four harsh winter days and nights they're put through the wringer. Whoever impresses most will be crowned Top Dog: the Best Rifleman in the Company.

Competing for this prize are Rifleman Callum Hancock, a former bouncer and powerlifter from Cornwall whose difficult family background serves as motivation to prove himself; Rifleman Will Halliday, the only Rifleman with A Levels, who's hoping brains can outsmart Hancock's brawn; and 18-year-old Rifleman Owen Morris, who, fresh into the army after being expelled from school, wants to show he's up to task.

Meanwhile, father of two Rifleman Ryan Dutton, is competing after a lengthy lay off from injury. Does he have the grit to prove to his superiors he is worth his place in the platoon?

Top Dog culminates in the 'Sword Lane', where exhausted soldiers must eliminate a series of targets at close range, using only a sword (The Rifles term for a bayonet).

After four hellish days in Wales, who still has the killer instinct?