The book "Tom Swift and His Big Tunnel" is a novel by Victor Appleton and follows the adventures of Tom Swift, the protagonist. In this novel, Tom and his friends travel to South America in search of a hidden city of the Andes that is said to be rich in gold and other valuable resources. Along the way, they face many challenges and obstacles, including treacherous terrain and dangerous wild animals, but they persevere and eventually discover the hidden city. Despite the challenges they face, Tom and his friends are able to overcome them and find success in their quest, bringing back wealth and treasures to their home country.