Tunnels and craters in the heart of a coalfield hide the bodies of soldiers from WW1 lying with their belongings, including a postcard that leads to Bavaria, the Storm Troopers and links to a young corporal called Adolf Hitler.
A First World War wristwatch found in a complex trench system in the churning sea of mud at Passchendaele, leads to descendants of a Welsh officer who died there. But all is not what it seems.
An enlisted man and an officer - WW1 brothers in death - are laid to rest. The men are identified through forensics, made possible because one of them broke a basic rule of war and the other carried his bankbook to the front.
Human bones reveal the partial remains of three men. A uniform button identifies them as Germans from the 213 Reserve Regiment and leads to the discovery of an atrocity committed near the birthplace of WW1 trench warfare.
The site of the bloodiest battle in WW1 yields evidence of a front-line medical post and the doctor who ran it - traced through a button that could only have been worn by one man at that place on that day.
In the First World War, men on horseback with swords fight against an emerging modern weapon, the machine gun. In Northern France, on the site of a cavalry charge into the face of relentless machine gun fire, the Trench Detectives discover evidence of a desperate act of bravery that stopped the German advance in the Spring of 1918, but decimated the ranks of a Canadian cavalry unit. It was the last great cavalry charge of the First World War, and it was made by Canadian soldiers.
In the second episode, the Trench Detectives discover the shattered remnants of a tank in French woodlands and try to trace its identity.
In the third episode, experts hope that a pair of matching wedding rings, found on an unknown soldier that fell on the Western Front in 1915, will help them identify the body.
In this episode, the team trace the history of a Canadian orphan.
The Trench Detectives dig into the past of a picturesque French hunting lodge, which was a silent witness to the war, to reveal its troubled history.
In this episode, the Trench Detectives attempt to discover what happened to a signaller who was stationed near a village in Belgium.
The Trench Detectives uncover the story of a civilian gravedigger serving on the Western Front, whose greatest fear was being buried alive.