The kids happen upon the legendary giant bullfrog, Benny Beelzebufo, who they once visited on his home river. Benny got off the Train at the wrong stop and is in new territory - the Pteranodon Family neighborhood. The kids take him around and show him fun places and play games with him. Then, he gets worried - he has to be home for dinner! A problem with the Dinosaur Train means our Pteranodon kids and Dad - with the help of good friend, Pauline Paleobatrachus, a tiny frog - take Benny on a trek over land and on water, and get him home to his family. Benny is thankful and loved his unexpected adventure with the Pteranodons. / When the kids all went to Junior Conductor's Academy, they met Dennis Deinocheirus, a brilliant and autistic theropod who was the first dinosaur kid who knew more dino facts than Buddy! Now, Dennis fulfills a promise and has come to visit Buddy and the kids at Pteranodon Terrace. Buddy, Tiny, Shiny, and Don play host to Dennis and are very sensitive to his needs, manner, and being out of his comfort zone. Dennis ends up having fun playing new games with the kids, digging holes, and playing on the pretend "Dinosaur Train" rocks.