The Pteranodon kids are spending the day with Grandma and Grandpa Pteranodon. On the Dinosaur Train on the way to their grandparents', Buddy, Tiny, Shiny and Don learn about sycamore trees. Grandma and Grandpa are so excited to have a whole day with their grandparents and doubly-excited to do a special "project" with them. They bring the kids to a field lined with sycamore trees and show them one tall one in particular that was - Can you believe it!? - planted by their Dad when he was a kid. Buddy, Tiny, Shiny and Don get to plant their own sycamore saplings and vow to visit their trees to track their growth as the months and years go by.