Karlemann is very often found in his own 'Robinson world', a secluded place on earth. There he travels the river in his special all-weather boat, and he has his domicile on the river: an imaginative, wildly romantic hut he built himself. One day he meets two soldiers of the National People's Army who got lost in Karlemann's empire. He shows the soldiers the right way. What Karlemann does not yet suspect: a bridge is to be built over the river at the exact spot where his hut stands...