The revised new edition of the classic: Justus has to memorize the Ten Commandments for school. But what is the point of that? His grandfather, with whom Justus builds a model airplane every afternoon, explains to him that the Ten Commandments are a kind of guide for a happy life. Through their afternoons spent in Grandpa's workshop, the two have plenty of time for extensive conversations. The grandfather becomes an important comforter, mediator, enlightener, advisor, and good listener for Justus's everyday worries. When the finished airplane finally soars high into the sky, Justus understands that the Ten Commandments also play a role in his daily life.