President Taft's cow, Pauline, is missing! She was carefully loaded into a special train car to deliver her to the Wisconsin Dairy Show. But she never arrived! How do you lose a cow? Helen Taft, the president's daughter, is determined to find her pet Pauline. Disguised in her brother's clothes she sneaks out of the White House leaving her cousin, Mary, to cover for her. But as Helen searches for clues to follow, she discovers Pauline is not the only one in danger. Someone is following her! When the clues lead her toward the Chicago slaughterhouse, Helen loses hope. Has Pauline been 'cow'-napped? Or has she already been made into hamburger?