Go and Stop are having fun playing at the beach. They see their friends the Three Bears building sandcastles. Little Bear's sandcastle looks very impressive, especially when Go puts a shiny shell on top. Medium Bear starts to make his, but when he tips his bigger bucket over, he just makes a sandy mess. Stop and Go realise that differently sized buckets need different amounts of sand. Big Bear's bucket is even bigger! Will they figure out how to fill her bucket and build another sandcastle?

Everyone's arriving for a special movie. Projectionist Secret Agent Chicken thinks she can make film night even better, but she doesn't realise the audience have arrived and are waiting for her to start the movie. Go and Stop try to get her attention with the help of Cow and the Do Blocks. Just when it seems like no-one is able to help, Go and Stop notice Slide Do Block in the audience. Can sliding the door get them into Secret Agent Chicken's projection room?