The villagers hold a go-kart race. Various fathers get over-excited about the race and cheat by adding electric engines, borrowed from Ted, to their kart. Pat and the children construct a proper pedal-kart with a wind-sail for extra speed (using natural power is not against the rules).
At the race the adults tear off in their karts, leaving Julian gamely bringing up the rear but the adults discover that their engines cant be stopped and PC Selby soon finds himself hurtling towards Greendale Crag. Pat leaps into the go-kart with Julian, fixes the windsail on the back, and rushes off after PC Selby.
They are able to divert him at the last minute from the edge of the crag and he goes hurtling into a big pile of manure. Pat and the kids collect the prize for the best go-kart and all the Dads are disqualified for cheating.