They went down a narrow stairway and carefully made their way through a dark, underground passage. Soon they came to a scattered heap of stones that marked the outlines of an old, old castle. "This is the very first castle that was built here," explained Anna. "It was built by Bishop Absalon in 1167, when Copenhagen was just a little fishing village. Here is the old well that has been used for hundreds of years," she said as they walked on farther, "and here is a part of the Blue Tower where Princess Leonora Christina was kept a prisoner for many years." "Oh, how could they keep anyone in such a terrible dungeon?" asked Greta, who shivered at the thought of spending even an hour in this gloomy place. "Let's go upstairs, Anna." "All right," agreed Anna. "I wonder how Chouse and the guard have been getting along." [Illustration: THE MARKET PLACE IN COPENHAGEN] The guard looked extremely worried when the girls appeared. Chouse was nowhere in sight. "I turned my back for just a minute," he said, "but when I turned around again your little dog was gone. He must have run outside, for you can see that he isn't here in the entrance hall." Greta was so upset that she couldn't say a word. "Come on, Greta. We shall have to go and hunt for him," said the practical Anna. "You go in one direction and I'll go in the other, and we'll meet here at Christiansborg in one hour." There wasn't anything for Greta to do but to start looking. There was no use in telling Anna that she didn't know one street from another. There was no use in saying that she didn't have the faintest idea of where to look. Anna had already started in the other direction and Greta heard her calling, every now and then, "Here, Chouse. Come, Chouse." So Greta started off bravely by herself. Christiansborg was built on a small island, so she crossed the Marble Bridge to the mainland and began walking slowly along the street by the side of the water. The shore was lined with fishing boats and on the sidewalk there were hundreds of little stands where the women were selling fresh fish which they took right out of the boats. Now and then Greta stopped to ask one of them if she had seen a little black and white dog. Not a one of them had seen him. [Illustration: FRESH FISH FOR SALE] [Illustration: WEIGHING A LOAD OF FISH] Greta decided that Chouse had not come along this street, so she walked back to the bridge and started down another street. Soon she came into a large open square filled with fruit and vegetable stands. The housewives of Copenhagen came here every morning during the summer to get the finest of fresh foods. Greta went from one stand to another, asking if they had seen her dog. Surely _someone_ had seen him. Finally she came to the very last stand, where a pretty girl was selling flowers. By this time tears had filled Greta's eyes and there was such a lump in her throat that she could hardly speak.