Shane Gulliver and Mark Tate (Treacle) are two ordinary 18 year-olds serving with the British Army in Iraq. Amidst constant insurgent attacks the platoon struggles to maintain the uneasy peace and to subdue a barrage of hostilities. When the popular company captain is killed on patrol by a roadside bomb, morale in the platoon hits rock bottom. Acting on orders they round up several suspects from house-to-house searches. That night feelings at the camp are running high and as the chain of command is weakened events spiral out of control. The Mark of Cain pulls you deep inside the Iraq conflict and shows you the true fear, horror and uncertainty of war.