The series follows the lives and adventures of racing vehicles Roary, Maxi, Cici, Drifter, Tin Top and the human people they work for, Big Chris and Marsha the mechanics and the owner of the race track Mr. Carburettor. Also there's P.C. Pete, local Farmer Green, Molecom, Flash and many more. The plot sometimes revolves around other vehicle characters, such as Rusty, FB, Nick, Plugger, Zippee, Hellie, Breeze, Conrod, James and Loada.