Perms, and catechism. No, Gretchen and Katie are not going through middle school again, they are walking through the Apostle's Creed in Luther's Small Catechism.
The Holy Spirit does what his name implies. He makes us holy. We believe in Jesus Christ, our Lord, and come to him only by the Holy Spirit who calls us with the gospel.
Scott and Caleb move into the Catechism's explanations of the Means of Grace. Starting with Baptism, Luther follows Scripture to explain how God's Word and promises are delivered to us through ordinary means like water.