Finn McMissile, a British spy, infiltrates the world’s largest untapped oil reserves owned by a group of lemon cars. After being discovered, he flees and fakes his death.
Lightning McQueen, now a 4-time Piston Cup champion, returns home to Radiator Springs to enjoy some quiet time, but when Italian formula race car, Francesco Bernoulli, challenges McQueen to the newly created World Grand Prix, led by its creator Sir Miles Axlerod, he and his best friend Mater — along with Luigi, Guido, Fillmore, and Sarge — depart for Tokyo for the first race of the Grand Prix. Meanwhile, the lemons, who are led by weapons designer Professor Zündapp and an unknown mastermind, secretly plot to secure their oil profits by using an Electromagnetic pulse emitter disguised as a camera (discovered by Finn on the oil platform) to trigger and destabilize the use of Allinol, a fuel that was created by Axlerod and required for racers to use in the Grand Prix. McMissile and his partner Holley Shiftwell attempt to meet with American spy car Rod “Torque” Redline at a World Grand Prix promotional event in Tokyo, to receive information about the mastermind. However, Redline is attacked by Zündapp’s henchmen, but not before passing his information to Mater before he is captured, who is then mistaken to be the American contact of Holley and Finn. Before killing Redline, Professor Zündapp finds out that Mater was given the information.
At the first race, three cars are ignited by the camera, and McQueen falls second in the race after Bernoulli, due to Mater accidentally giving him bad racing advice shortly after evading Zündapp’s henchmen with help from Holley and Finn. Mater is soon abducted by Finn and boards his plane, where he helps to identify some of the information he was given. After traveling to Paris to get more information from Finn’s old friend, they travel to Italy, where the next race is being held. While the race is being held, Mater infiltrates the criminals’ meeting, just as the camera is used on a few more cars, causing a multi car pileup, while allowing McQueen to finish first. Due to the criminals plan causing Allinol to be perceived as troublesome, Sir Miles Axlerod removes it as a required fuel for the final race. However, when McQueen decides to continue using it, the criminals plot to kill McQueen in the next race in London, which spooks Mater, causing him to blow his cover and allow him, Finn and Holley, to be abducted.