Little Tim Tammer, the son of a lighthouse keeper, lives right on the Baltic Sea beach, but his remote home often leaves him feeling lonely. When Young Pioneers pitch their tents nearby, he is overjoyed and quickly makes new friends.

His parents give him permission to travel with the other children to Cape Sundevit. First, though, he has to run an errand, which ends up taking much longer than he had hoped because others keep asking him for help. Tim returns to find the Pioneers already gone, but he sets off to follow them to Cape Sundevit.

Based on a children's book by Benno Pludra.