Germany invades mainland Britain. Stormtroopers swarm ashore along the South Wales beaches, determined to capture the Welsh Steelworks and Coal Mines.

Newport is blitzed. Irishman Danny O’Shea’s house is bombed and his wife is killed. His young son Adam has learning difficulties. Terrified of what the Nazis will do to him, O’Shea tries to take him to neutral Ireland.

Penniless and desperate, they head for Fishguard. But on an isolated Welsh road they witness an attack on a German convoy by Welsh Nationalists. The convoy is carrying some mysterious boxes that were discovered in a secret laboratory near Brecon.

German Captain Eric Weiss, responsible for the boxes safe transfer to Berlin, knows that his job - even his life - depends on him getting them back.

But, following a major disagreement amongst the Welsh insurgents, the boxes disappear. Then O’Shea goes to the aid of a dying woman - and both the Germans and the insurgents believe she’s told him where the boxes are.

Suddenly O’Shea is separated from his son and catapulted into a world of betrayal and brutal double-cross. Pursued by both the Germans and the insurgents, his only concern is to find Adam and get him to safety.