When the train passes Grandpa's house, Gus is so excited that he runs outside to wave at the cars. He forgets all about Grandpa's dog, and Skipper escapes through the open gate. It takes Grandpa to get him back. Then, when Grandpa decides to look for Daddy's old toy train, Gus leaps into the act, and they are so absorbed that they both forget Skipper. Together, they find him. Later, Gus and Grandpa plan to ride a real train. But when they get on, they realize that they're in trouble — Grandpa has forgotten where he put the tickets (but not for long). In the third Gus and Grandpa book, Claudia Mills and Catherine Stock evoke all the joy of trains — and of remembering.