Time Team turns its trowels on the Shorncliffe Redoubt, an earthwork fortification in Kent built during the Napoleonic Wars to help repel a feared French invasion. The archaeologists excavate the site to work out how the fort's design functioned defensively and how it doubled as a training ground for light infantry, the unit tactics that would go on to reshape the British army. Trenches reveal the layout of ramparts and buried structures, while specialists piece together how soldiers drilled and lived on the site, connecting the physical remains to written records of the period. The team situates the redoubt within the broader chain of coastal defenses raised against 'the old enemy' across southern England, and considers what the site's survival, and its role in shaping modern infantry training, says about Britain's response to the invasion threat. As with other Time Team digs, the pleasure is watching interpretation build in real time as finds come out of the ground.