A bridge is dynamited, and Burt Ottman is accused of the crime. Penny Parker isn't convinced that he's guilty. She works with an old man, Noah, to find answers. But can she prove Burt's innocence? Find the answers to this and more in Saboteurs on the River!This book is from the Penny Parker series by Mildred A. Wirt, also known as ghostwriter Carolyn Keene, of the Nancy Drew series of books.