Cars 2 features Mater as an accidental spy.
In the 2011 sequel, Mater travels abroad with Lightning McQueen and becomes entangled in Finn McMissile's investigation. Because of a misunderstanding, the British agent believes Mater has valuable intelligence, and Mater is pulled into a plot involving espionage, sabotage, and an alternative fuel campaign.
The film expands the Cars setting beyond Radiator Springs and racing by visiting international locations and using the structure of a spy adventure. McQueen remains a major character, but Mater's accidental-agent storyline drives much of the sequel's comedy and action.
Cars 2 is different in tone from the original Cars, which focuses on McQueen's personal change after his stay in Radiator Springs. Cars 3 returns to a more race-centered story about McQueen's career and his rivalry with Jackson Storm.