Christian Kempenich is the Chief Clerk in the Town Council in a small town on the river Mosel in Germany. He goes to Cologne to attend a family baptism, and afterwards is lured to sample the wicked delights of the big city. He wakes up the next morning in a cheap hotel room with no memory of what happened, but there's a strange woman asleep in the bed with him. Horrified, he heads home with his guilty secret. Meanwhile his wife went on the river steamer to the next town; an Italian tenor has been giving her singing lessons and has amorous intentions towards her, and he takes the same steamer. They stay on it to Koblenz and have to stay the night. The rest of the film revolves around Kempenich and his wife as they alternately show guilt about their own behaviour and outrage as they learn what their spouse might have done.