S1, E5: The team travels to western France to get to the bottom of a mystery that originally seems to date back to the First World War, but actually has its roots even further back in history. When a British tank inscribed with the name Joan is discovered underground, it looks like its occupants were murdered in a horrific war crime. But as the Bonekickers delve further into their research they find that, although the tank is British, the dead soldiers are both British and German. Gillian gets news that her mother is seriously ill, and despite the best efforts of Vivian and the rest of the team, refuses to leave the dig. The team uncovers a daring conspiracy involving two sets of enemy soldiers whose shared passion for the past which lead them to try and work together for peace in the midst of major conflict, a plan that could have changed the course of European history.