Some time after defeating Jackson Storm, Mater informs his friends at Radiator Springs that he'll be leaving the town for a few days to attend the wedding of his sister, Mato. Lightning McQueen offers to accompany him, and the two go on a road trip to the wedding. At Lightning's insistence, the two stop at a dinosaur museum, where Mater is scared by the dinosaur statues. Mater falls asleep and dreams of him and Lightning as cavemen, being attacked by dinosaurs. He later wakes up, no longer afraid thanks to his dream, before leaving the park with Lightning. (thetvdb.com)