One sunny afternoon, Paul meets his friends, Cat Kira and Dog Douglas at the playground and they play a fun guessing game. “I see something you don’t see, and it is ... blue!” calls out Paul. Kira and Douglas look around and start guessing. “The sky?” – “The slide?” – “That car over there?” – “The ocean!!!” calls a voice from over their heads. “I’ve seen it from the air plenty of times.” Paul and his friends look up in surprise. It’s the parachuting frog making another of his brave jumps and landing cheerfully in the sandpit. Then he folds up his parachute and hops away quickly.
Kira and Douglas keep guessing what Paul could mean, but they just can’t work it out. “The last carriage of my uncle Engineer Egon‘s train is blue!” calls out Paul finally. “Look, over there, the engine is at the train station!” “Oh, that was really difficult!” complains Kira. “Hey, have you ever seen the ocean? I haven’t,” says Douglas. Paul and Kira shake their heads. “What about we ask your uncle if he can take us to the seaside?” asks Douglas. Paul and Kira think it’s a wonderful idea. Paul’s uncle is very nice and says he would be happy to take them on a daytrip to the seaside – but first they have to get permission from their parents. They plan to head off tomorrow.
Paul can hardly sleep because he’s so excited and can hardly wait to finally see the ocean! That night Douglas gets a sore throat and fever, so he can’t go with Paul and Kira. “Have fun at the seaside!” calls Paul’s mum “We’ll pick you up here again tonight.” The locomotive toots goodbye loudly, starts to move and quickly leaves Kullerbü station behind.
Paul and Kira enjoy the wind in their faces and the beautiful scenery – golden fields and green meadows where happy cows graze. A little while later, behind another curve, they catch sight of the beautiful blue ocean. The seagulls screech in the air and there are lots of sun umbrellas, lounge chairs and beach chairs on the long, golden, sandy beach. “We’ve arrived!” calls out Engineer Egon as he brings the train to a stop in the nearby station. While the carriages are being unloaded then loaded with new cargo, Uncle Egon has time to go down to the ocean with Paul and Kira.
The first thing he does is buy each of them a big ice cream, then they explore the beach together. The waves have little white foamy crests, and lap at the shore. Kira and Paul giggle happily the whole time. Finally they find a nice place to build a sand castle. Uncle Egon helps them, then makes himself comfortable in a beach chair to have a little rest.
In no time at all the day at the seaside is over. Paul and Kira are sad that it’s already time to go home. Before they leave they take a picture of the ocean as a souvenir. And as they climb back into the train, Paul calls out “Bye bye ocean. We’ll come back to visit again soon!”