The cameras follow L Company as they attempt to try and track down Taliban spies who have been reporting on their movements.

Chris Terrill joins L Company on a dangerous operation.

Chris Terrill’s coverage of active service in Afghanistan continues, with the focus turning to the dogs. The men of L Company risk getting blown up every day by IEDs (improvised explosive devices). The area they patrol is riddled with them and four marines have been killed in less than three months. So four-year-old springer spaniel Memphis is brought in to help. With his super-sensitive nose Memphis has a knack of sniffing out IEDs and should save a lot of lives and limbs. Meanwhile, a mile to the north, the Royal Engineers are still busy clearing IEDs from the old bazaar at the village Loy Mandeh. It is slow, painstaking work but once again dog power is being used to detect the deadly bombs. Unlike Memphis, however, Vidar suffers from a terrible fear of loud bangs. Luke Outhwaite, his handler, has to comfort the Belgian shepherd dog every time an IED is detonated.

The Royal Marines of 42 Commando are given orders to engage the Taliban on their turf. Having spent weeks venturing near to the traditional Taliban strongholds in Nad Ali North, only to be warned off, the Commandos need to test the threat. A fighting patrol, led by Seargeant Taff Hunter is despatched directly into the insurgents' heartland to tackle the Taliban head on.

This week, Chris joins the Royal Marines in Nad Ali North as they begin to hand over control of security to the Afghan National Army and police. For the Royal Marines of 42 Commando, the handover can be frustrating as the Afghans do things very differently. M Company launch an airborne operation into a known Taliban heartland in the desert of Helmand Province. Accompanied by the Afghan National Police, the operation takes an unexpected turn from the start…

The Royal Marines of 42 Commando prepare to return back to the UK after their six-month deployment to one of the most dangerous parts of Afghanistan. Out of 100 men, seven marines were killed in action and over 50 suffered life-changing injuries. Among the wounded are Simon Maxwell, Mick McConnell and Paul Vice – all victims of IED blasts. The military mission they were part of was deemed a great success, but their lives will never be the same again.