The guys feel the need to save trees and gasoline, so they convert a small pickup truck to run one wood. They get a set of plans from Sweden and proceed to build the conversion unit, similar to what was done all over Europe during WWII when gasoline was in short supply. They interface with a local UK environmental group and eventually donate the truck to them. The drama come in when they can't get the vehicle running on the wood gas that is made from burning wood chunks in an oxygen-starved environment. So they get an expert from Sweden to come to the UK to help them out. Once the truck is running well, they drive it around, even through the streets of London at night.