Lucy Wilson has lost her best friend! Normally this would cause her great distress, but when Hobo's body is hijacked by her Grandad, Brigadier Lethbridge-Stewart, Lucy is over the moon. Soon they find themselves hurtling back in time, where in 1937 the young Brigadier and his brother James find themselves face-to-face with smugglers. What connects 1937 and 2018? Lucy Wilson and the Brigadier are about to find out, as they join the Bledoe Cadets in solving the mystery at Redgate Smithy, especially when the price will be high for at least one of the Cadets! But for Lucy and her Grandad, it is a chance to understand what truly binds them together, what it is to be a Lethbridge-Stewart!