Stories about children separated from parents — whether that is because of death (The Lion King, Bambi) or something a little less sad (Finding Nemo) — are a grand Disney tradition.In the new trailer for the upcoming Disney/Pixar film The Good Dinosaur, we find that the same fate befalls the movie's hero, Arlo. Arlo is swept up by a waterfall, and finds himself alone without his poppa. Thus he must go on a grand adventure bound to make us cry big messy tears.All alone, Arlo meets a rambunctious little boy named Spot and they become inter-species pals. It seems that there are many surprising allies in the world of The Good Dinosaur, a world where an asteroid did not hit Earth, eliminating the dinosaurs. Take, for instance, the seemingly wise and benevolent T-Rex, voiced, unmistakably, by Sam Elliott. Arlo and Spot, are also seen roaring alongside the T-Rexes.Will Arlo get home? Will Spot be the Dug or the Boo of the movie? Will this movie rival the emotional impact of Disney-Pixar's other release this year, Inside Out? We will find out when it arrives Nov. 25.