This episode sees Rick and Beau head to the vast River Trent, site of one of the greatest strongholds of the English Civil War – Newark Castle. In the first official search of the waterway, the River Hunters will be searching for lost Civil War relics that reveal the secrets of this brutal battleground. The duo start their search directly next to the castle and find evidence from the key advances in warfare at the time, which eventually helped lead to the King's demise. They also discover musket balls among other lost items that help picture the harrowing life in this turbulent time.