The Fieldhouse Brothers, from Somerset, take on the Bueno Brothers, originally from Spain, in a closely fought first semi-final to build jaw-dropping chain reaction machines that will allow Richard to dust his ornaments without leaving bed. With a place in the final at stake and a challenge that requires delicacy and creativity, the contraptions need to be extra special. Chain reaction machine guru Zach Umperovitch is the expert judge and Shini Somara fills in the science behind the teams' eccentric contraptions.

Engineering enthusiasts from around the UK competing to create the best chain-reaction machines from everyday objects. Each episode sees the contestants' efforts scored by judges based on the contraption's ingenuity and quality. One team is then voted off, with a winner crowed in the final episode of the series.