In Karsten and Petra's Summer Book, we have combined two stories about Karsten and Petra.
In Karsten and Petra Want to Learn How to Swim, Karsten and Petra are on a boat trip with Grandpa and his girlfriend, Esther, and they stop on an island. Neither Karsten nor Petra can swim, but they still have fun in the water, and after a while they even dare to dive down and put their heads completely underwater! So it seems that Karsten and Petra will most certainly learn how to swim soon. In Karsten and Petra Goes On A Trip, the two go on a family camping trip.