Mats is very impressed with an old book he found in a chest in the attic. It is about a boy scout named Walter, who is always very happy because he performs at least one good deed every day. Without hesitation, Mats decides to copy Walter. He is actually feeling quite unhappy at the moment because he has moved to another town with his parents. But it's not quite so easy to help people. He tries with his parents, with the people in his house, an old woman in the street whose bag he wants to carry home - but everywhere, Mats gets into trouble. And then there is the matter of the donation for starving children in Africa ... Mats begins to have doubts: has he chosen the right role model for himself?